Pistorius was told his trial would begin March 3 during a hearing in Pretoria. South Africa does not hold trials by jury, so a judge will determine the verdict. The trial will run until March 20.
Before the hearing, Pistorius wiped away tears and held hands with his family members. At times, he appeared to be praying.
Pistorius made history in 2012, becoming the first double-amputee to compete at the Olympics against able-bodied opponents. He has become known as the "Blade Runner" because of the shape of his carbon-fiber prosthetics.
He said he mistook Steenkamp for an intruder and shot her through a locked bathroom door. Prosecutors allege the shooting was premeditated, and that he and Steenkamp had been sleeping in the same bed before he shot her.
They allege that Pistorius put on his prosthetics and followed her to the bathroom where he intended to kill her, shooting four shots through a closed bathroom door. Pistorius said he did not put back on his famous blades.
Evidence in the trial will include cell phone records from Pistorius' home and examination of the bathroom door -- the angle or trajectory of the bullets could show whether Pistorius was standing on what is left of his legs, as he said, or whether he put on his prosthetics.
Lawyers for Pistorius are pushing to have the charges reduced to culpable homicide. If they are unable to have the charges reduced, Pistorius will get a sentence of life imprisonment with a minimum service time of 25 years.