He avoided looking at the public gallery, where June Steenkamp was sitting.
Pistorius entered the court before 10am to stand trial for allegedly murdering Steenkamp last year.
He was ushered into the court through a side entrance and took a cushion as he sat down in the dock. He was wearing a grey suit, took a sip of water and shrugged his shoulders.
He was seen talking to his defence team, and whispering into his advocate Barry Roux’s ear.
Pistorius, 27, faces charges of premeditated murder and contravening the Firearms Control Act in a trial which is expected to last at least three weeks.
The proceedings in the wood-panelled courtroom will be broadcast live on television and radio, with the initial indictment listing 107 witnesses to testify for the State.