He made history in London last year when he became the first double-amputee track athlete to compete in the Olympic Games.
He is known as the “blade runner” because of the carbon fibre prosthetic blades he races in. He was born without a fibula in both legs and had his legs amputated below the knee before his first birthday.
Police were called to his home in the early hours of Thursday morning.
They found paramedics treating a 29-year-old woman with four gunshot wounds to the head and upper body. She died at the scene, and officers recovered a 9mm pistol.
Early reports suggested Mr Pistorius might have mistaken his girlfriend for an intruder.
South African Olympic and Paralympic athlete Oscar Pistorius has arrived at court to face a murder charge after his girlfriend, model Reeva Steenkamp, was shot and killed at his home near Pretoria.
Mr Pistorius spent the night in a police station and is appearing at the magistrates’ court in the city.
A decision will be taken on whether he should be granted bail.
Prosecutors will argue that Mr Pistorius should remain in custody.
The athlete arrived at court in the back of a police vehicle, hiding his face with a jacket and a notepad.
Dozens of photographers are in the courtroom in Pretoria, where chief magistrate Desmond Nair will hear the bail application.
The BBC’s Andrew Harding, at the scene, says it is likely that some details of both the case against the 26-year-old, and his defence, will be revealed.
Television cameras have been allowed in court for the hearing. Members of Mr Pistorius’s family, including his sister and father, are in the courtroom.
Mr Pistorius has undergone medical and DNA tests. His lawyer, Kenny Oldwage, said his client was “very well, obviously emotional, but fine”.
The defence is expected to argue that Mr Pistorius is not a flight risk and should be given bail.
Forensic experts are expected to continue examining the house in the upmarket Silver Woods gated community on the outskirts of South Africa’s administrative capital where Ms Steenkamp, 29, died.
Correspondents say the athlete’s arrest has stunned the country where he is considered a national hero.
But a police spokeswoman said that investigators were “very surprised” by that report, adding: “These allegations did not come from us.”
Police say neighbours heard screaming and shouting around the time of the shooting, and that they had been called to investigate incidents of a domestic nature at the same house in the past.
Mr Pistorius and Ms Steenkamp had reportedly been dating since November.
Oscar Pistorius was born without fibula bones and had both legs amputated at the age of 11 months.
Mr Pistorius dominated in his category at successive Paralympic Games, but in 2008 he won a legal battle over his blades – which critics said gave him an unfair advantage – with the International Association of Athletics Federations (IAAF) for the right to compete in able-bodied competitions.
He reached the 400m semi-finals in the London 2012 Olympics. At the Paralympics he won silver in the T44 200m, gold in the 4×100 relay and gold in the T44 400m, setting a Paralympic record.
South Africa has one of the highest rates of crime in the world and many residents keep weapons to protect themselves against intruders.
But gun ownership is strictly regulated and it is not easy to obtain a licence.
By BBC News