Adduci, Mastriani & Schaumberg LLP

Louis S. Mastriani

Louis S. Mastriani
t: 202-467-6300
f: 202-466-2006
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  • District of Columbia Bar
  • State Bar of California
  • New York State Bar Association
  • Federal Circuit Bar Association
  • American Bar Association (Member, Sections on International Law and Litigation)
  • ITC Trial Lawyers Association


  • Whittier College, J.D.
  • Marquette University, B.A.


  • California
  • District of Columbia
  • New York
  • U.S. Court of Appeals for the Federal Circuit
  • U.S. Court of Appeals, Second Circuit
  • U.S. Court of Appeals, Fourth Circuit
  • U.S. Court of Appeals, Ninth Circuit
  • U.S. Court of Appeals, Eleventh Circuit
  • U.S. Court of International Trade
  • U.S. Court of Federal Claims
  • U.S. Court of Appeals for Veterans Claims
  • U.S. Supreme Court

Louis S. Mastriani is a founding partner of Adduci, Mastriani & Schaumberg, LLP. Lou counsels and assists clients in domestic and worldwide licensing and enforcement programs for intellectual property rights, with an emphasis on high technology patent portfolios.

For forty years, Lou has been involved in unfair competition investigations before the U.S. International Trade Commission (ITC) under Section 337, as well as intellectual property litigation in federal district courts. He also handles antidumping and countervailing duty investigations at the ITC and the U.S. Department of Commerce and cases before the U.S. Court of International Trade and the U.S. Court of Appeals for the Federal Circuit. He has been involved over the years in interacting on behalf of domestic and foreign clients with U.S. Customs in matters involving the administration and enforcement of ITC exclusion orders, protection of intellectual property rights, as well as valuation and classification matters, including appeals to the U.S. Court of International Trade and the U.S. Court of Appeals for the Federal Circuit.

Prior to entering private practice, he served as legal counsel to an ITC Commissioner before becoming a senior investigative attorney in the Office of Legal Services (currently known as the Office of Unfair Import Investigations). As a senior ITC investigative attorney, Lou assisted in revising and drafting the Commission's Rules of Practice and Procedure with respect to Section 337 investigations. While at the ITC, he also litigated numerous Section 337 investigations on behalf of the public interest involving patent, non-patent, and antitrust issues, including self-initiated 603 investigations.

Lou was appointed by the U.S. Trade Representative to serve as both a panelist and a chairman on bi-national panels convened pursuant to the North American Free Trade Agreement to provide review of antidumping and countervailing duty decisions.

Lou has lectured extensively and published articles on international trade issues and intellectual property protections. 

Adduci, Mastriani & Schaumberg, L.L.P. is a Washington D.C. law firm and internationally recognized leader in the field of international trade law with an emphasis on Section 337 intellectual property litigation before the United States International Trade Commission (ITC).  Founded in 1981, the firm has over 30 years of experience practicing before the ITC, all other federal agencies involved in international trade, the United States Court of International Trade, and federal district and appellate courts.  As part of its Section 337 practice, the firm has participated in approximately one-third of all investigations instituted in the last ten years.  In other areas of international trade law, the firm represents clients in antidumping and countervailing duty proceedings, as well as advises clients on Customs valuation and classification, and on country of origin, duty preference programs, sanctions, and export control issues. The firm also advises clients on trade policy issues, including import and export opportunities and barriers, enforcement, and regulatory hurdles.  In addition to its international trade practice, the firm represents clients in a broad range of intellectual property disputes and counsels them on licensing and enforcement.

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