The South African Olympian left Kgosi Mampuru II prison on Monday evening, a day earlier than expected, and was released to his uncle’s home in Pretoria.
He will have to serve the remainder of his five year sentence under house arrest.
The 28-year-old athlete, lovingly termed ‘blade runner’ at the height of his career, shocked the world in 2013 when he shot and killed his model girlfriend Reeva Steenkamp.
Claiming he mistook his 29-year-old partner for an intruder in his home, Pistorius shot through the locked bathroom door at his Pretoria home, killing Reeva.
But at the trial in 2014, Pistorius was found not guilty of murder, and instead convicted on the lesser charge of Culpable Homicide.
A case lodged by the prosecution says they believe his conviction should be uplifted to murder - and this will be heard at the Supreme Court in November.
"Oscar Pistorius was placed under correctional supervision tonight," a spokesman from the prison confirmed.
It is thought he was released a day early, and under cover of darkness, to avoid the media glare that would no doubt follow the athlete.
The South African is thought not to be electronically tagged, but will have restrictions on his movement, as well as being prevented from owning guns.
He will also be required to attend psychotherapy sessions.
Steenkamp’s family have spoken previously about their feelings on the time served, saying a year just is ‘not enough for taking a life.’