The Paralympic champion shot and killed his then-girlfriend Ms Steenkamp in his Pretoria home in the early hours of February 14, 2013 and was subsequently charged with her "wilful and intentional murder".
After pleading not guilty to the charge in March 2013, a lengthy court process found Pistorius guilty of a lesser charge of culpable homicide in September 2014, before Judge Thokozile Masipa sentenced the South African to a maximum sentence of five years in prison.
Pistorius served one fifth of his sentence before being released from prison on house arrest. However, prosecutors said the application of the law had not been correct in the case and South Africa's Supreme Court of Appeals subsequently ruled that his conviction should be changed to murder due to the "errors of law" and a "proper appraisal of the facts".
Here we look back at the key dates in proceedings over the past 34 months.
February 14, 2013 - Pistorius shoots and kills Ms Steenkamp in his home in Pretoria and is arrested.
August 19, 2013 - A trial date is set for the case, with the hearing due to start on March 3, 2014 and originally set to conclude on March 20.
March 3, 2014 - Pistorius pleads not guilty to the charge of wilful and intentional murder, as well as other firearms offences.
March 6, 2014 - Pistorius breaks down in court as the death of Ms Steenkamp is described. Four days later, Pistorius is physically sick as the nature of Ms Steenkamp's injuries are described, and vomits in court again on March 13 when images of the deceased are shown.
March 25, 2014 - The prosecution, led by Mr Gerrie Nel, rests its case.
April 7, 2014 - Pistorius takes to the stand as the defence opens its case. He apologises to the family of Ms Steenkamp. "I can't imagine the pain and the sorrow and the emptiness that I've caused you and your family."
April 15, 2014 - The cross-examination of Pistorius by the prosecution concludes and Pistorius steps down from the stand.
May 14, 2014 - Judge Masipa orders Pistorius to undergo psychiatric testing.
May 20, 2014 - It is announced that Pistorius will spend 30 days as an outpatient at Weskoppies Psychiatric Hospital from May 26.
June 30, 2014 - Pistorius is declared fit for trial after a report concluded that he did not have a mental disorder at the time of the shooting and was "capable of appreciating the wrongfulness of his act".
July 8, 2014 - Pistorius' defence, led by Mr Barry Roux, rests its case.
July 15, 2014 - Pistorius is involved in a nightclub fracas after being "aggressively engaged" about his trial.
August 7, 2014 - Closing arguments begin.
August 8, 2014 - It is announced that Judge Masipa will deliver her verdict on September 11.
September 11, 2014 - Judge Masipa rules that Pistorius cannot be found guilty of premeditated murder. "The state clearly has not proved beyond reasonable doubt that the accused is guilty of premeditated murder," she says. "There are just not enough facts to support such a finding."
September 12, 2014 - Pistorius is found guilty of culpable homicide, which carries a maximum prison sentence of 15 years. He is also found guilty in one count of discharging a firearm in public, which carries a maximum of five years. He is granted bail, with a sentence hearing set to commence on October 13.
October 13, 2014 - The sentencing begins, with the defence suggesting community sentence as an appropriate punishment.
October 21, 2014 - Judge Masipa sentences Pistorius to a maximum of five years in prison. For the firearms charge, he is sentenced to three years suspended for five, to be served concurrently.
October 27, 2014 - Prosecutors announce their decision to appeal the verdict and sentence handed to the South African athlete.
December 10, 2014 - Judge Masipa gives the state leave to appeal Pistorius' acquittal.
October 20, 2015 - Pistorius released from Kgosi Mampuru Correctional Centre on house arrest after serving one fifth of his sentence, staying with family in Pretoria.
December 3, 2015 - South Africa's Supreme Court of Appeals announce ruling to change verdict from culpable homicide to murder, a charge that carries a minimum sentence of 15 years. The high court in Pretoria will reconvene to determine a fresh sentencing on the new conviction.