The trial was moved to a high court and is scheduled to run until March 23. If convicted of murder, he faces life in prison.
Double-amputee Pistorius, 26, known as Blade Runner for the prostheses he wears in competition, bowed his head and held his hands in prayer with his brother Carl and sister Aimee before the brief hearing in a Pretoria court yesterday.
Detailed charges were presented in an indictment outlining the prosecution's case of premeditated murder against Pistorius, who has admitted shooting Ms Steenkamp, a fashion model and aspiring TV star, through a bathroom door at his Pretoria home on February 14, Valentine's Day.
Pistorius, who was released on bail in February, claims he was acting in self-defence against what he thought was an intruder. Yesterday's court hearing was held on the day Ms Steenkamp would have turned 30.
Pistorius was also handed a lesser charge of violating provisions of the firearms control act for having 38 rounds of unlicensed ammunition at his home.
Endorsement deals for the likes of sports giant Nike have been either suspended or cancelled since his arrest over his girlfriend's death.