Zuma did not show up at the inquiry led by Deputy Chief Justice Raymond Zondo in February, after which prosecutors approached the court seeking an order for his imprisonment.
J udge Sisi Khampepe said on Tuesday: “The Constitutional Court can do nothing but conclude that Mr Zuma is guilty of the crime of contempt of court."
South Africa President Blasts Anti-Corruption Report as Unfair
Zuma, 79, has been accused of plundering state coffers during his nearly nine years as president.
Khampepe said of Zuma: “This kind of recalcitrance and defiance is unlawful and will be punished. I am left with no option but to commit Mr. Zuma to imprisonment, with the hope that doing so sends an unequivocal message…the rule of law and the administration of justice prevails."
“The majority judgment orders an unsuspended sentence of imprisonment for a period [of 15 months],” she declared, ordering Zuma to turn himself in within five days.
Zuma's spokesperson told South Africa’s eNCA television channel that the ex-president would issue a statement sometime soon.
The inquiry commission was proposed by Zuma himself, after pressure mounted over scandals, just before he was ousted in 2018 by the ruling African National Congress (ANC).
Yet Zuma testified just once, in July 2019, after staging a walkout days later, accusing the commission’s Zondo of bias.
Zuma ignored numerous invitations to reappear in court due to medical problems as well as preparations for a simultaneous corruption hearing.
Zuma then appeared again briefly in November but left before questioning, after which Zondo asked the Constitutional Court to intervene.
Most of the corruption cases investigated by the commission involve three brothers from a wealthy Indian business family, the Guptas, who earned lucrative government contracts and allegedly chose cabinet ministers.
Zuma is facing 16 distinct charges of fraud, corruption, and racketeering over a 1999 purchase of fighter jets, patrol boats, and military gear from five European arms firms for 30 billion rands (nearly $5bn).
Zuma was then-President Thabo Mbeki’s deputy at the time of the arms purchases.