Former Paralympic and Olympic athlete shot the 29-year-old model dead through a locked bathroom door on Valentine’s Day in 2013.
The former Paralympic champion once celebrated as the 'blade runner' - was granted parole in November and today left a South African jail and is now at home, South Africa's correctional services department said.
Pistorius shot Reeva Steenkamp on Valentine's Day in 2013 at his home in Pretoria, it is said that the 37-year-old said he fired his gun through a bathroom door after mistaking her for an intruder. Prosecutors said the killing was premeditated and he shot Ms Steenkamp after she fled to the toilet following a row.
The parole will last until December 2029 and Pistorius will be subject to restrictions and supervised by a correctional services official.
Some of the parole conditions include restrictions on when he will be allowed to leave his home, a ban on consuming alcohol and orders he must also attend therapy for anger issues and "gender-based violence issues". He will also have to perform community service.
He will have to regularly meet with parole officers and will be subjected to unannounced visits by authorities. He will have to inform a Department of Corrections official of any major changes in his life, such as if he wants to get a job or move to another house.
He was expected to stay in his uncle's Pretoria mansion and will not be allowed to leave the Waterkloof district without permission.
In a statement shared by the Steenkamp family lawyer, Ms Steenkamp's mother said: "Has there been justice for Reeva? Has Oscar served enough time? There can never be justice if your loved one is never coming back, and no amount of time served will bring Reeva back.
"We, who remain behind, are the ones serving a life sentence," June Steenkamp said. "With the release of Oscar Pistorius on parole, my only desire is that I will be allowed to live my last years in peace with my focus remaining on the Reeva Rebecca Steenkamp Foundation, to continue Reeva's legacy."
She said the conditions imposed by the parole board had affirmed her belief in the South African justice system as they "send out a clear message that gender-based violence is taken seriously"
He could be sent back to jail if he breaches any of his parole conditions.