The ex-Buffalo Bills running back, whose case is being closely followed by many millions of Americans, frowned unhappily as the judge bound him over without bail to face two charges of first-degree murder with 'special circumstances' - offences which potentially carry the death penalty.
The judge, Kathleen Kennedy-Powell, told the court, whose proceedings were broadcast nation-wide on US network television, that there was 'ample evidence' to suggest 'a strong suspicion' that Mr Simpson was guilty of killing his ex-wife, Nicole Brown Simpson, and her friend, Ronald Goldman, a 25-year-old aspiring male model. The victims were found stabbed to death outside Ms Simpson's home in Los Angeles last month.
The judge's decision ended a six-day preliminary hearing at Los Angeles Municipal Court in which Mr Simpson's team of lawyers sought to prove that prosecutors did not have sufficient evidence to bring a case against him. The prosecution were only required, at this stage, to prove that they had 'probable cause' to believe him guilty - which the judge accepted. He will be arraigned in court on 22 July.
The ruling came after a day of dramatic evidence in which both sides in the case revealed key parts of their strategy. Earlier, Gregory Matheson, head of the Los Angeles Police serology laboratory, told the court that spots of blood found near the murder scene matched O J Simpson's blood type, but not that of the victims. He said that only about 0.43 per cent of the population had the same blood type. But Robert Shapiro, Mr Simpson's attorney, argued that they comprised more than 40,000 people in Los Angeles alone.