South Africa's Supreme Court of Appeal on Friday extended the sentence of Oscar Pistoriou to 13 years and five months.
He was initially sentenced to six years in prison for the murder of his girlfriend Riva Steenkamp.
However, the prosecutor's office had ruled at the time that the sentence imposed on him was "shockingly forgiving" and appealed.
The Olympian was jailed last July, when he was found guilty of killing his girlfriend on Valentine's Day in 2013.
The athlete was not in the courtroom on Friday.