Peter S. Gilster

Of Counsel


  • Missouri
  • Illinois
  • U.S. District Court, Eastern District of Missouri
  • U.S. Court of Appeals, Eighth Circuit
  • U.S. Court of Appeals, Federal Circuit
  • U.S. Supreme Court
  • U.S Patent & Trademark Office


J.D., University of Illinois College of Law, 1965

B.S., University of Illinois at Urbana–Champaign, 1962


Peter Gilster is a registered patent attorney before the USPTO & Canada with a degree in electrical engineering. As senior patent counsel, Peter has been involved in patent prosecution matters involving electrical engineering, advanced electronic technology, sophisticated electronic solid state materials and semiconductor technology.

Peter’s patent practice has emphasized communications, electronic systems, devices and software, electro-mechanical and mechanical arts, solid state electronic and display devices, medical technology, medical treatment and substances, transdermal medications, automotive and aviation technologies.

Peter primarily focuses his practice on patent prosecution but is also available to assist on patent and technology-related issues as they arise in litigation, counseling and corporate transactions.

In the area of patent prosecution, Peter typically handles domestic and international patent filings, filing and prosecution of PCT International Patent Applications, filing and prosecution of European Patent Office (EPO) patent applications, and filing and prosecution of Foreign National Phase Patent applications. Before the Patent and Trademark Office, he has handled appeals from adverse examiner decisions in the PTO and inter partes proceedings PTO patent interference proceedings and contested re-examinations. He has testified as an expert in patent law in a limited number of patent infringement lawsuits.

Although Peter has been involved in many federal court intellectual property litigations throughout his career, he now primarily serves in an advisory and technical support role on patent and technical, engineering and technology related issues that arise in patent, trade secret, unfair competition and technology based litigation.

Peter served in the Army Reserve as an ROTC graduate and was an Army captain during the Vietnam conflict.

Professional Affiliations

  • The Missouri Bar
  • Illinois State Bar Association
  • American Bar Association
  • Bar Association of Metropolitan St. Louis
  • Federal Communications Bar Association
  • American Association for the Advancement of Science
  • ACLU
  • ACS
  • WAC
  • Institute of Electrical and Electronics Engineers, life member
  • University of Illinois Alumni Association
  • Lawyer-Pilots Bar Association
  • Aircraft Owners and Pilots Association

Community/Civic Activities

  • St. Louis County, Missouri, Health Group Volunteer

Honors & Awards

Honors & Awards

  • Martindale-Hubbell, AV-Preeminent

News & Insights



  • Author, firm monographs relating to Intellectual Property Law
  • “Missouri Deskbook on Intellectual Property Law”
  • “Chapter 30: Patent Law”
    Missouri Deskbook on Business Organizations, 2001 & 2003