Grand Upright Music, Ltd v. Warner Brothers Records, Inc., 780 F.Supp. 182 (S.D.N.Y. 1991), was a copyright case heard by the United States District Court for the Southern District of New York. The court granted an injunction against the defendants to prevent further copyright infringement of the plaintiff's song by sampling and referred them for criminal prosecution. The judgment helped change the conduct of the rap and hip hop music industries, guaranteeing that any future music sampling would be preapproved by the original copyright owners to avoid a lawsuit.

Biz Markie, a Warner Brothers rap musician, had sampled three words and a portion of the music from the song "Alone Again (Naturally)" by singer/songwriter Gilbert O'Sullivan, for use in Markie's third album, I Need A Haircut. Biz Markie and his production and recording companies were listed as co-defendants with Warner Brothers in the subsequent lawsuit.

Judge Kevin Thomas Duffy granted an injunction against the defendant, Warner Brothers Records, despite Warner Brothers' claim that that Grand Upright did not own a valid copyright in the sampled song. Warner Brothers denied that Grand Upright owned the copyright to the song, though Grand Upright produced documentation that O'Sullivan had transferred title to them, and O'Sullivan himself testified to that regard. It also appears that the defendants unsuccessfully urged the court to take note of how common unapproved sampling was in the industry, because the court noted that "the defendants...would have this court believe that stealing is rampant in the music business and, for that reason, their conduct here should be excused."

The decision received some criticism for stating that "the most persuasive evidence that the copyrights are valid and owned by the plaintiff" was that Warner Brothers had previously attempted to obtain permission to use the song. However, this would not legally establish that Grand Warner was in fact the owner, but only that Warner Brothers' believed that the song was copyrighted by someone, which would make their infringement knowing and willful. As Grand Upright had provided evidence that specifically established the copyright was theirs, the ruling did not hinge on this point, however.

The court wrote that "it is clear that the defendants knew that they were violating the plaintiff's rights as well as the rights of others. Their only aim was to sell thousands upon thousands of records. This callous disregard for the law and for the rights of others requires not only the preliminary injunction sought by the plaintiff but also sterner measures." The judge then referred the matter to a United States Attorney for criminal prosecution due to the defendants' intentional copyright infringement.