Karim Z. Oussayef

Karim Z. Oussayef

PHONE: 212-351-3427 FAX: 212-351-3401
Karim Oussayef's practice focuses on patent infringement and licensing, trade secrets and related litigation. Mr. Oussayef has represented clients in a variety of industries, including computer networks, VOIP telephony, cable television, e-commerce, and web and mobile applications, encryption and compression technologies, antibody therapies, skin graft medical devices, and vehicle insurance. Mr. Oussayef has also served as pro bono counsel in matters including political asylum applications and not for profit intellectual property licenses.

Before joining Desmarais LLP, Mr. Oussayef was an associate in the Intellectual Property Litigation group of Ropes & Gray LLP.

Prior Experience

  • Associate, Ropes & Gray LLP, New York, New York, 2008-2011


  • United States District Court for the Eastern District of New York, 2010
  • United States District Court for the Southern District of New York, 2010
  • United States Court of Appeals for the Federal Circuit, 2014

Other Distinctions

  • New York Metro Rising Star (2017)
  • New York Metro Rising Star (2016)
  • New York Metro Rising Star (2015)
  • New York Metro Rising Star (2014)


Representative Matters

  • Represented IBM in patent litigation against Groupon resulting in a $82.5 million jury verdict finding that all four e-commerce patents at issue were valid and willfully infringed.  Successfully argued and defeated patent-eligibility challenges at hearing on the pleadings.  Successfully argued claim construction at Markman hearing.  Successfully argued and defeated Groupon’s motion for summary judgment of non-infringement at summary judgment hearing.  Examined IBM’s technical expert witness and cross examined three Groupon witnesses, including Groupon’s technical expert witness, at trial.
  • Represented IBM in patent litigation against Priceline, OpenTable, and Kayak concerning website and online systems technology.  Overcame repeated challenges to IBM’s patents in district court and before the patent office, and ultimately secured a favorable settlement shortly before trial was scheduled to begin.
  • Represented LifeCell Corporation against TELA Bio, Inc. in a trade secret and unfair competition case involving surgical mesh products.
  • Defended Cisco, ARRIS, Time Warner Cable, and several other entities in patent infringement actions involving 29 patents asserted by a non-practicing entity, Rockstar, created by Apple, Microsoft, Ericsson, Sony, and Blackberry.  Managed team of attorneys from several law firms engaged in simultaneous district court actions and patent office proceedings. 
  • Represented GSK in a patent litigation against Genentech concerning technology for manufacturing and purifying monoclonal antibody products.
  • Defended IBM in a patent litigation brought by IP Venture concerning server load-balancing technologies.  Deposed the inventors of the patents-in-suit and developed non-infringement and validity arguments that helped lead to a favorable settlement for IBM during summary judgment briefing.
  • Defended Cisco in a patent infringement action involving encryption technology filed by VirnetX, a non-practicing entity.  VirnetX asserted six patents against virtually all of Cisco’s product line, including switches, routers, voice-over-IP phone systems, and VPN products.  VirnetX had previously won jury trial verdicts of $368 million against Apple, and $108 million against Microsoft (leading to a $200 million settlement).  Prepared witnesses and developed claim construction, non-infringement, and invalidity positions as part of the a team that secured a jury verdict rejecting VirnetX’s $258 million damages claim against Cisco.
  • Defended Liberty Mutual in a patent infringement action against Progressive involving vehicle monitoring technology.  Drafted a motion that successfully stayed litigation during interpartes review of Progressive patents before the United States Patent and Trademark Office, which eventually invalidated all of the claims at issue.
  • Represented Realtime Data in a patent litigation case against a variety of network device manufacturers in a patent litigation involving compression technologies.  Realtime Data achieved favorable settlement on the eve of trial.
  • Extensive experience advising clients about patent valuations, licenses, and assertions in a variety of circumstances, related to litigation and otherwise.


  • Sasha Rao & Karim Oussayef, Structurally Similar, But Effectively Different?, Pharma Magazine November/December 2010, at 68.
  • Karim Oussayef, Selective Privacy: Facilitating Market-Based Solutions to Data Breaches by Standardizing Internet Privacy Policies, 14 B.U. J. Sci. & Tech. L. 104 (2008).


Boston University School of Law, J.D., 2008, magna cum laude, Executive Editor of the Journal of Science & Technology Law

University of Rochester, B.S., 2004, cum laude, Computer Science with High Departmental Distinction


2009, New York

2008, Massachusetts



230 Park Avenue,
New York, New York 10169
Phone: 212-351-3400
Fax: 212-351-3401