Mario J. DeRossi

Mario J. DeRossi

also known as DeRossi Law Firm, LLC

4.9
Rating: 10.0

Licensed for 24 years

Divorce and separation Lawyer at Mineola, NY
Practice Areas: Divorce & Separation, Family, Child Custody, Child Support

100 Old Country Road, Suite 301, Mineola, NY

About Mario

Biography

Fees and Rates

We have not found any cost information for this lawyer


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Licenses

Licensed in New York for 24 years

State: New York

Acquired: 2001

Currently Registered

No misconduct found

Licensed in Massachusetts for 24 years

State: Massachusetts

Acquired: 2001

Inactive

No misconduct found

Location

DeRossi Law Firm LLC

100 Old Country Road, Suite 301, Mineola, NY, 11501

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Mario J. DeRossi's Reviews

Avvo Review Score

4.9 /5.0

113 Client Reviews

Posted by Lisa | May 4, 2025 | Hired Attorney

This review is from a person who hired this attorney.

Good lawyer

Excellent lawyer,give great advice,Mario and his team explain everything thing clearly and answer all my questions. Great staff.

Posted by Stephen | August 2, 2024 | Hired Attorney

This review is from a person who hired this attorney.

Stephen Cowden

I was referred to Mario by a friend of mine, and from the moment I contacted him I could see that he’d be very easy to deal with and very professional. He showed me that what I’m going through many people have gone through before and that even though this is an emotional process, that will get thr...ough it together, and he was absolutely correct. He instilled confidence from day one is able to bring me through step-by-step. he explained the law and easy to understand manner. I was always able to reach Mario or someone at his office would get back to me in a very timely manner and he would let me know when our communication would have to be in person by phone rather than email. I would highly recommend Mario without reservation as he made a very difficult process seem relatively easy and I got through a very contentious divorce and resolution with his expertise.

Posted by anonymous | July 31, 2024 | Hired Attorney

This review is from a person who hired this attorney.

Professional, knowledgeable, and experienced

Mario was very professional and has a great staff. He has lots of experience and vast knowledge of the law. I highly recommend Mario and his staff.

Posted by Ann | December 13, 2023 | Hired Attorney

This review is from a person who hired this attorney.

Simply the best!

Mario is absolutely the best!!! I felt very confident having him as my lawyer. He explained everything very well and walked me through the entire process, which can be very overwhelming. He was reachable, honest, and fought for me. I knew from our first meeting that I was in great hands. You will no...t be disappointed!

Posted by Lauren | November 10, 2023 | Hired Attorney

This review is from a person who hired this attorney.

Absolute Professional

Mario expertly & compassionately took me through the arduous process of a child support case. Not only did he keep me informed of what to expect at every turn, but he made sure that I comprehended what was happening and what the possible outcomes were. Additionally I received what I think was the bes...t possible result. I couldn’t be happier with Mario’s services.

See All Client Reviews

Mario J. DeRossi's Lawyer Endorsements

Endorse Mario
Michael Robert Gionesi headshot
Michael Gionesi

Divorce and separation lawyer | Sep 17

Relationship: Fellow lawyer in community

"A powerful and zealous advocate for his clients, Mario has earned the respect of his peers and the judiciary. His level of civility is second to none, which makes him an even more effective advocate. His effectiveness is surpassed only by his keen intellect. I wholeheartedly endorse him."

Michael Drew DiFalco headshot
Michael DiFalco

Divorce and separation lawyer | Sep 19

Relationship: Opposing Counsel on matter

"I endorse this lawyer. Mario is an excellent attorney. We've had a couple of cases together and he's a zealous advocate for his clients while remaining a gentleman."

Somair Syed Alam headshot
Somair Alam

Divorce and separation lawyer | Feb 13

Relationship: Fellow lawyer in community

"Exceptional attorney, dedicated to client success. Highly recommended."

Joshua Bradley Hecht headshot
Joshua Hecht

Divorce and separation lawyer | Oct 02

Relationship: Fellow lawyer in community

"Mario is an exceptional attorney. His knowledge of family law matters is impressively extensive, but more importantly she has a deep focus on the needs of her clients. Highly recommended!"

Barry J. Gross headshot
Barry Gross

Divorce and separation lawyer | Jan 22

Relationship: Opposing Counsel on matter

"I endorse this lawyer. Mr. DeRossi is an extremely talented and knowledgeable attorney. He is "old school" in that his word is his bond."

Frederick William Vasselman headshot
Frederick Vasselman

Divorce and separation lawyer | May 29

Relationship: Worked for lawyer

"I endorse this lawyer."

Susan Ann Kassel headshot
Susan Kassel

Divorce and separation lawyer | May 17

Relationship: Opposing Counsel on matter

"I endorse this lawyer. Mario is always well prepared, clever and quick on his feet. He is an excellent attorney."

John M O'Brien headshot
John O'Brien

Commercial real estate lawyer | May 14

Relationship: Fellow lawyer in community

"A truly excellent attorney well respected in the legal community. I wholeheartedly recommend him to anyone looking for a lawyer who knows the law and truly cares about protecting the rights of his clients and getting them the most favorable result possible."

Christopher Daniel Leroi headshot
Christopher Leroi

Divorce and separation lawyer | Sep 15

Relationship: Fellow lawyer in community

"Mr. DeRossi is an outstanding attorney who provides exemplary advice on Avvo. I would recommend everyone and anyone to him for representation. Even though I have been practicing fo 24 years, as a judge, magistrate, prosecutors, and in private practice, I learn valuable new information from him every day. A superb attorney."

Howard M Lewis headshot
Howard Lewis

Divorce and separation lawyer | Jun 09

Relationship: Fellow lawyer in community

"I endorse this lawyer. Attorney DeRossi is an outstanding attorney with an exceptional reputation. He is a strong and zealous advocate for his clients and a credit to the legal profession. I highly recommend his legal services."

Ivan E. Young headshot
Ivan Young

Divorce and separation lawyer | Apr 10

Relationship: Fellow lawyer in community

"Having known Mario for a few years now, I can firmly state that he is a gifted attorney that advocates for his Client's in a manner rivaled by few. Not only does Mario have a profound knowledge of the law, but he truly is personable and attentive to his Clients which gives all those that go to him a genuine sense of comfort in such a stressful situation. I would and do recommend Mario to all Clients seeking representation in matrimonial related issues."

Jason Adam Isaacson headshot
Jason Isaacson

Divorce and separation lawyer | Oct 11

Relationship: Opposing Counsel on matter

"A strong advocate and always professional, Mr. DeRossi is an experienced attorney who offers practical solutions to resolve difficult issues."

Robert Scott Grossman headshot
Robert Grossman

Family lawyer | Jun 21

Relationship: Opposing Counsel on matter

"Mario and i were adversaries in a contested matrimonial case. I found him to be knowledgeable, a true professional, and most importantly, a man of his word."

Matthew Scott Seidner headshot
Matthew Seidner

Family lawyer | Mar 20

Relationship: Fellow lawyer in community

"Mr. DeRossi has an excellent reputation not only among other attorneys but before the bench. It is a privilege to consider him a colleague in an area of law that requires not only intelligence but compassion and patience."

Jill Altarac headshot
Jill Altarac

Divorce and separation lawyer | Nov 14

Relationship: Opposing Counsel on matter

"I have had several matters with Mr. DeRossi, and he is a strong advocate for his clients. Mr. DeRossi is very professional and works diligently to assist his clients achieve their intended results."

Caitlin Donahue headshot
Caitlin Donahue

Family lawyer | Aug 16

Relationship: Opposing Counsel on matter

"Mr. DeRossi displays an impressive level of professionalism and integrity while representing his clients. Not only does he have an obvious command of the law, but also places a high priority on maintaining the trust of opposing counsel."

Christian Aaron Pickney headshot
Christian Pickney

Divorce and separation lawyer | Aug 28

Relationship: Opposing Counsel on matter

"In a divorce case I handled against Mr. Derossi he represented his client zeaolously and professionally. He protected his client's rights and did not engage in unnecessary litigation that would have wasted our client's money and time. He knows the law and conducts himelf professionally. It was my privilege to work with this attorney."

Brian C. Pascale headshot
Brian Pascale

Personal injury lawyer | Aug 05

Relationship: Worked together on matter

"I endorse this lawyer's work. He is an amazing, detail oriented, and professional litigator."

Joseph DiBenedetto headshot
Joseph DiBenedetto

Divorce and separation lawyer | Apr 30

Relationship: Worked together on matter

"I endorse this lawyer's work. Mario is very competent and considerate of his client's needs. Mario has repeatedly obtained exceptional results for his clients."

View All Endorsements
Joseph Steven Dujmic Jr. headshot
Joseph Dujmic

Divorce and separation lawyer

Michael Robert Gionesi headshot
Michael Gionesi

Divorce and separation lawyer

Lawrence Bruce LaRaus headshot
Lawrence LaRaus

Divorce and separation lawyer

Michael Drew DiFalco headshot
Michael DiFalco

Divorce and separation lawyer

Joshua Bradley Hecht headshot
Joshua Hecht

Divorce and separation lawyer

Barry J. Gross headshot
Barry Gross

Divorce and separation lawyer

Frederick William Vasselman headshot
Frederick Vasselman

Divorce and separation lawyer

Howard M Lewis headshot
Howard Lewis

Divorce and separation lawyer

Karina Alomar headshot
Karina Alomar

Divorce and separation lawyer

Ivan E. Young headshot
Ivan Young

Foreclosure lawyer

Kenneth John Ready headshot
Kenneth Ready

Personal injury lawyer

Jason Adam Isaacson headshot
Jason Isaacson

Divorce and separation lawyer

Matthew Scott Seidner headshot
Matthew Seidner

Divorce and separation lawyer

Jill Altarac headshot
Jill Altarac

Divorce and separation lawyer

Caitlin Donahue headshot
Caitlin Donahue

Family lawyer

Christian Aaron Pickney headshot
Christian Pickney

Divorce and separation lawyer

Joseph DiBenedetto headshot
Joseph DiBenedetto

Criminal defense lawyer

Brian C. Pascale headshot
Brian Pascale

Personal injury lawyer

Experience

Rating:  10.0 (Superb)

Honors

2025

Super Lawyer, Super Lawyers

2024

Super Lawyer, Super Lawyers

2023

Super Lawyer, Super Lawyers

2022

Super Lawyer, Super Lawyers

2021

Super Lawyer, Super Lawyers

2020

Super Lawyer, Super Lawyers

2019

Super Lawyer, Super Lawyers

2018

Super Lawyer, Super Lawyers

2017

Super Lawyer, Super Lawyers

2016

Rising Star, Super Lawyers

2015

Rising Star, Super Lawyers

2014

Top 40 Under 40, The National Trial Lawyers

2014

2014 New York Metro Rising Stars, SuperLawyers

2014

Top Ten Ranking, The National Academy of Family Law Attorneys

2014

Top 40 Lawyer Under 40, The American Society of Legal Advocates

2014

Rising Star, Super Lawyers

2004

Award for Trial Advocacy, The Association of the Bar of the City of New York

2003

Army Commendation Medal, Trial Defense Service, United States Army

2003

Bronze Star Medal, Fourth Infantry Division, United States Army

2002

Army Commendation Medal, Fourth Infantry Division, United States Army

Work Experience

2009 - Present

Partner, Stern & DeRossi, LLP

2006 - 2009

Associate, Stern, Adler & Associates, LLP

2002 - 2006

Judge Advocate, United States Army

Associations

2014 - Present

The National Academy of Family Law Attorneys

Member

2014 - Present

The American Society of Legal Advocates

Me

2009 - Present

Nassau County Bar Association

Member

2009 - Present

New York State Bar Association, Family Law Section

Member

2009 - Present

Columbian Lawyers Association

Member

Education

2001

Saint John's University, School of Law

Juris Doctor

Languages

English

Activity

Avvo Rating

Our Rating is calculated using information the lawyer has included on their profile in addition to the information we collect from state bar associations and other organizations that license legal professionals. Attorneys who claim their profiles and provide Avvo with more information tend to have a higher rating than those who do not.

What determines Avvo Rating?
  • Experience & background Years licensed, work experience, education
  • Legal community recognition Peer endorsements, associations, awards
  • Legal thought leadership Publications, speaking engagements
  • Discipline Disciplinary information may not be comprehensive, or updated. We recommend that you always check a lawyer's disciplinary status with their respective state bar association before hiring them.
Avvo Rating Levels
10.0 - 9.0 Superb8.9 - 8.0 Excellent7.9 - 7.0 Very Good6.9 - 6.0 Good5.9 - 5.0 Average4.9 - 4.0 Concern3.9 - 3.0 Caution2.9 - 2.0 Strong Caution1.9 - 1.0 Extreme Caution