The double-amputee track star last month escaped a murder conviction in a verdict that shocked the country and fueled criticism of South Africa's legal system.
Kicking off what is expected to be a lengthy sentencing process, the defense team will bring mitigation arguments before Judge Thokozile Masipa in the High Court in Pretoria. Prosecutors will follow by arguing for aggravating circumstances.
The process is expected to last up to four days, with Masipa then likely adjourning court and announcing her sentencing decision at a later date.
The "Blade Runner" could face as much as 15 years in one of South Africa's notoriously brutal prisons or could dodge a jail term altogether with a non-custodial sentence after being found guilty on the equivalent of a manslaughter charge, but not guilty of premeditated murder.
The court will begin by hearing defense witnesses testify on why Pistorius should not serve time behind bars.
They are likely to argue that the country's prisons are not suited for his disability and that the 2012 London Paralympics silver medalist is a first time offender.
Lawyer David Dadic said the defense will "heavily expand on their trial argument regarding Oscar's remorse-fulness" in killing his girlfriend of Reeva Steenkamp.
"The biggest factor, however, which the defense will raise is, of course, the fact that Oscar is a first time offender," he added.
In turn, the state will call witnesses to testify on why he should serve the stiffest penalty, raising the issue of his history of negligence with firearms. After the sentence is handed down, both the state and defense can appeal, a legal process likely to drag out for years.
In September, Judge Masipa ruled the 27-year-old did not knowingly shoot to kill 29-year-old model and law graduate Steenkamp on Valentine's Day 2013.
The sprinter admitted he fired four hollow point bullets through a locked toilet door in his upmarket Pretoria home, but said he believed he had been shooting at a burglar.
Masipa's ruling outraged many South Africans, including lawyers who believed she misinterpreted the definition of murder and questioned whether the justice system is failing the crime-plagued country.
Pistorius is currently out on bail of one million rand (USD 90,000). He had to sell his posh house inside a gated compound in Pretoria, the scene of the crime, to fund the cost of the trial, and has withdrawn from competitive sport since his arrest.

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