United States v. Paramount Pictures, Inc., 334 US 131 (1948) (also known as the Hollywood Antitrust Case of 1948) was a landmark United States Supreme Court case that dramatically changed the way Hollywood movies were produced, distributed, and exhibited. The Court held in this case that the existing distribution scheme was in violation of the antitrust laws of the United States, which prohibit certain exclusive dealing arrangements.

The legal issues had its genesis with the silent era, when the Federal Trade Commission began investigating film companies for potential violations under the Sherman Antitrust Act of 1890.

Ultimately, the main issue of monopolization would be the reason behind all the major movie studios being sued in 1938 by the U.S. Department of Justice. The case reached the U.S. Supreme Court ten years later. The verdict went against the studios, forcing all of them to divest of their movie theater chains.

The court orders forcing the separation of motion picture production and exhibition companies are commonly referred to as the Paramount Decrees. While Paramount was forced to sell its own theater chain (which merged with the American Broadcasting Company, former United Paramount Theaters boss Leonard Goldenson leading ABC for decades), it is today controlled by another theater chain, National Amusements (through its control of Viacom, which was created by, divested as a result of another antitrust action by, and now owns, CBS as well). However, it seems unlikely that a vertically integrated motion picture business will ever be revived.

Consequences of the decision include:

• more independent producers and studios to produce their film product free of major studio interference;
• the end of the Golden Age of Hollywood;
• the loss of the studio's rights to their own classic film libraries, especially in the wake of the rise of television.

Film libraries

The studios that suffered the most were Warner Bros., United Artists, and Paramount Pictures.

• WB sold the rights to its classic library to Associated Artists Productions , which would later become part of UA; these rights returned to Time-Warner after a series of acquisitions.
• UA sold a majority of its sound library to an entity that would later become the rechristened Republic Pictures (although other companies and estates of UA stars/producers also hold rights to other components of the UA catalog).
• EMKA, Ltd. (the outlet of MCA) acquired most of Paramount's sound library up to the 1948 ruling.

Universal, 20th Century Fox, MGM, and Columbia Pictures were able to keep the rights to their libraries, although, decades later, Ted Turner would purchase the pre-1986 MGM library that Time-Warner would later acquire.