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Mary B. Matterer

Partner T: 302.888.6960 F: 302.571.1750
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Mary B. Matterer has practiced patent litigation in the District Court of Delaware for more than 15 years. She frequently serves as Delaware counsel for law firms well known for their experience in patent and complex commercial litigation. She currently serves as a member of the U.S. District Advisory Committee for the Delaware District Court.

Her practice consists of diverse forms of litigation, including intellectual property, commercial, and complex insurance coverage litigation. Mary primarily handles patent litigation across a wide range of industries, including pharmaceuticals, telecommunications, automotive, biomedical, electronics, and internet/software. She successfully defended the City of Wilmington against a claim of copyright infringement brought by a former employee. The District Court of Delaware found on summary judgment that the copyright belonged to the city under the work made for hire doctrine, and that decision was affirmed by the Third Circuit Court of Appeals.

She has also represented insurance companies in multimillion dollar disputes involving demands for coverage with respect to environmental and products liability claims under general liability policies, and also demands for coverage under directors and officers policies. She has served as Liaison Counsel for insurers where numerous insurers were brought into the lawsuit. She represented an excess insurer regarding liability for defense costs incurred by Intel in defending against claims of anticompetitive activity. Summary judgment of no liability for such costs was granted in favor of this and other insurers.

Mary is praised by her clients, who appreciate her familiarity with the courts, as well as by judges who find her “confident, responsive, and flexible,” according to Chambers USA - America's Leading Lawyers for Business, 2008. She was again cited by Chambers USA in 2012 “as a source of confidence; clients particularly highlighting her coolness under pressure and ability to make progress in a tense environment."



  • Patent infringement (ANDA) claims
  • Insurance disputes

American Law and Legal English Institute

Mary combines her background in linguistics and law by frequently lecturing at the University of Delaware on the topic of intellectual property as part of the American Law and Legal English Institute for foreign attorneys and judges.

Professional Affiliations

Delaware State Bar Association, International Law Section, Former Chair
American Bar Association, Intellectual Property and Litigation Sections

Community Affiliations

Returned Peace Corps Volunteers of Delaware Association, 2005-Present

Recent Matters

Boehringer Ingelheim Intern. GMBH v. Barr Laboratories, Inc.
Patent Infringement -ANDA

Impax Laboratories, Inc. v. Aventis Pharmaceuticals Inc.
Patent Infringement-ANDA

AT&T Corp. v. Clarendon American Ins. Co.
Insurance coverage dispute

In re '318 Patent Infringement Litigation
Patent Infringement-ANDA

AT&T Corp. v. Faraday Capital Ltd.
Insurance coverage dispute

Wyeth v. Impax Laboratories, Inc.
Patent Infringement-ANDA

AT&T Corp. v. Clarendon America Ins.
Insurance coverage dispute

LML Patent Corp. v. Telecheck Services, Inc.
Patent Infringement-Electronic Checking Technology

Royal Indem. Co. v. General Motors Corp.
Insurance coverage

Shire Laboratories v. Impax Laboratories
Patent Infringement-ANDA

Liggett Group, Inc. v. Ace Property and Cas. Ins. Co.
Insurance coverage for tobacco claims

ABB Flakt, Inc. v. National Union Fire Ins. Co. of Pittsburgh, Pa.
Insurance coverage

E.I. du Pont de Nemours & Co. v. Allstate Ins. Co.
Insurance coverage for pollution claims

Hoechst Celanese Corp. v. Certain Underwriters at Lloyd's London
Insurance coverage for leaky plumbing fixtures

Coalition to Save Our Children v. State Bd. of Educ.
Federal Supervision of Wilmington Schools

Continental Cas. Co. v. General Battery Corp.
Insurance coverage

Monsanto Co. v. Aetna Cas. & Surety Co.
Insurance coverage

Monsanto Co. v. American Centennial Ins. Co.
Insurance coverage

Bristol-Myers Squibb Co. v. Mylan Pharmaceuticals Inc.
Patent Infringement-ANDA (efavirenz)

CareFusion 303 Inc. v. Hospira, Inc.
Patent Infringement-medication management system

Cephalon Inc. v. Impax Labs. Inc.
Patent Infringement-ANDA (Fentora)

Collarity, Inc. v. Google Inc.
Patent Infringement-search phrase refinement to aid in computer searches

Commonwealth Research Group LLC v. Cypress Semiconductor Corp
Patent Infringement- system for conserving energy among electrical components

CyberFone Systems LLC v. CNN Interactive Group Inc.
Patent Infringement-Telephone device and system for entering data into databases

DataCarriers L.L.C. v. Research in Motion Corp.
Patent Infringement-proactive presentation of automating features to a computer user

Eon Corp. v. FLO TV
Patent Infringement-software controlled multi-mode interactive tv systems

Abbott Labs. V. Impax Labs. Inc.
Patent Infringement-ANDA (Simcor)

American Guarantee & Liability Ins. Co. v. Intel Corp.
Insurance Coverage for legal fees regarding antitrust activity claims

Le v. City of Wilmington
Copyright Infringement – instant ticketing computer software

News & Media Mentions

Mary was cited by Chambers USA as a source of confidence; clients particularly highlighting her coolness under pressure and ability to make progress in a tense environment.

Practice areas


Delaware Today®, Top Lawyers, 2014-2016

Chambers USA - Recognized for Intellectual Property Law, 2008-2016

Best Lawyer®, 2009-2017

Corporate INTL Magazine®, "Attorney of the Year in Delaware," 2014

Delaware Journal of Corporate Law, Law Review


Ruby Vale Summer Clerkship, Delaware Superior Court

Clerk for The Honorable John E. Babiarz, Jr., Delaware Superior Court


Delaware, 1988

United States District Court, District of Delaware

U.S. Court of Appeals, Third Circuit


Widener University School of Law, J.D., cum laude, 1988

Ohio University, M.A.,1979

University of Delaware, B.A.,1971