The surgeon once dubbed "Dr Death" has been found guilty of killing three patients and permanently injuring another.

After about 50 hours of deliberation, the Brisbane Supreme Court jury in the manslaughter trial of Jayant Patel announced it had finally reached a verdict about 5.40pm (AEST) on Tuesday.

Patel arrived back in court flanked by his lawyers and his wife Kishoree, who has been present for the duration of his 15-week trial.

Stony-faced, he stood in the dock as the jury announced he was guilty of the manslaughter of Mervyn Morris, Gerardus Kemps and James Phillips.

The jury also found him guilty of causing grievous bodily harm to Ian Vowles.