Sarah A. Pfeiffer


Sarah Pfeiffer specializes in intellectual property litigation, with an emphasis on patent litigation.  Her experience spans all phases of litigation, including pleadings, discovery, expert discovery, contentions, summary judgment, pre- and post-trial advocacy, and appeals. Ms. Pfeiffer also has experience in patent post-grant proceedings, including inter partes reviews and reexaminations.  She has litigated cases throughout the U.S., including California state and federal courts, the Eastern District of Texas, Delaware, and the Eastern District of Virginia.

Ms. Pfeiffer has represented clients in many industries, including consumer electronics, consumer apparel, medical devices, pharmaceuticals, and media.  Ms. Pfeiffer has experience litigating, prosecuting, and negotiating agreements relating to many technologies, including: software, hardware, graphics processing, memory, digital photography, navigation and mapping, mechanical devices, and chemicals.

In addition to intellectual property litigation, Ms. Pfeiffer has experience in other areas of litigation.  Ms. Pfeiffer has litigated cases in the fields of antitrust, commercial contracts, criminal, false advertising, and labor.


Boston University School of Law. J.D.

Arizona State University. B.S. Chemical Engineering


State of New York

State of California

District of Columbia

Northern District of California

Central District of California

U.S. Patent and Trademark Office

Prior Experience

Before joining MSF, Ms. Pfeiffer was an attorney with an AmLaw 100 firm for over five years.  Prior to that, she was an associate with an intellectual property boutique firm.  Ms. Pfeiffer also worked as an engineer prior to attending law school, working as a project engineer for one of the world’s largest construction companies and as a process engineer for a semiconductor manufacturing equipment supplier.

Representative Matters

Represented consumer electronics company in E.D. Tex. defending against patent infringement claims relating to graphics processors.

Represented internet search provider in Delaware and N.D. Cal. defending against patent infringement claims relating to navigation, mapping, and satellite images.

Represented fitness tracking software provider in D. Utah defending against patent infringement claims relating to mobile software.

Represented large multimedia company in E.D. Tex. defending against patent infringement claims relating to digital encoding.

Represented airline in N.D. Cal. defending merger against private antitrust claims.

Represented the people of California while working as a temporary placement Deputy District Attorney in Orange County, California.  Took three misdemeanor cases to trial through jury verdict and conducted numerous felony preliminary hearings and evidentiary motion hearings.