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Additional Licenses

  • U.S Patent & Trademark Office

  • U.S. District Court for the Eastern District of Missouri

  • Eighth Circuit Court of Appeal

  • Court of Appeals for the Federal Circuit

  • U.S. Supreme Court



  • Mr. Gilster has been involved with over 20 federal lawsuits involving intellectual property issues. These have involved various issues of intellectual property, including prosecution of patent infringement, patent validity, defense of patents, appropriation of trade secrets, unfair competition and trademark infringement. As a partner in the former intellectual property firm of Kalish & Gilster (which merged into Peper, Martin, Jensen, Maichel and Hetlage), Mr. Gilster was involved with the late well-known advocate and patent lawyer Ralph W. Kalish, Sr., in numerous federal cases.

  • He has been involved in many controverted unlitigated matters, often involving patent infringement and validity. He has also handled appeals from adverse examiner decisions in the Patent and Trademark Office and so also has handled inter partes proceedings in the Patent and Trademark Office including patent interference proceedings and contested re-examinations.

  • Mr. Gilster has testified as an expert in patent law in some patent infringement lawsuits.


Languages spoken: Spanish

Photos and videos

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Practice areas


  1. Intellectual Property: 65%
    49 years
  2. Patent Application: 18%
  3. Patent Infringement: 10%
    49 years
  4. Licensing: 3%
  5. Other: 4%
  6. More 

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Contact info

Greensfelder, Hemker & Gale, P.C.

10 S. Broadway
20th Floor
St. Louis, MO, 63102

Suite 2000
10 South Broadway
St. Louis, MO, 63102-1774



MOGood Standing, Active196801/08/2013
ILActive And Authorized To Practice Law196511/12/2015
We have not found any instances of professional misconduct for this lawyer.
Avvo contributions
Legal answers
Award nameGrantorDate granted
Marquis Who's Who in the WorldMarquis Who's Who2009
Who's Who in American LawyersMarquis Who's Who1999
Marquis Who's Who in Americamarquis Who's Who in American Law1999
Who's Who in the Worldmarquis Who's Who in American Law1999
Martindale av-ratingMartindale-Hubbell1987
Work experience
TitleCompany nameDuration
OfficerGreensfelder, Hemker & Gale, P.C.1999 - Present
PartnerBlackwell Sanders Peper Martin1997 - 1999
PartnerKalish & Gilster Law Offices1977 - 1996
Patent LawyerMonsanto Company1972 - 1977
Patent LawyerKoenig, Senniger, Powers & Leavitt1967 - 1972
CaptainUnited States Army1965 - 1967
Association namePosition nameDuration
Illinois State Bar AssociationMemberN/A
Missouri State BarMemberN/A
American Bar AssociationMemberN/A
American Intellectual Property Law AssociationMemberN/A
International Trademark AssociationMemberN/A
Federal Bar AssociationMemberN/A
Lawyer Pilots Bar AssociationMemberN/A
Publication nameTitleDate
UnknownMissouri Deskbook on Intellectual Property Law2004
UnknownMissouri Deskbook on Business Organizations2003
UnknownMissouri Deskbook on Business Organizations2001
School nameMajorDegreeGraduated
University of Illinois College of LawLawJD - Juris Doctor1965
University of Illinois, Urbana-ChampaignN/AOther - Bachelors1962
Speaking engagements
Conference nameTitleDate
Adjunct Professor Univ. of MissouriPatent Law for Engineers2003
St. Louis Center for Emerging TechnologyPatenting Medical Inventions in Europe2002
Lecturer in Patent LawPatent Law International Protection2002
St. Louis World Trade CenterInternational Practice Aspects in The IP Field1996