Aggrey Kiyingi, who built a medical practice in suburban Sydney, after migrating with his spouse from Uganda in the late 1970s, will be put on trial in Kampala on March 1.
Robinah Kiyingi had been a high-profile lawyer who railed against corruption and rights abuses in Uganda.
The Kiyingis, who had three children, had been separated.
Ms Kiyingi was gunned down in her car outside her Kampala home by men who escaped on a motorcycle, witness have said.
Her body was left riddled with at least seven bullets.
Investigations into the July 11 slaying have been complicated by the mysterious death in prison of one co-defendant as well as the gunning down of a key police detective.
Mr Kiyingi, 51, was arrested after he flew to Uganda to attend her funeral.
Since then he has been held at Kampala's Luzira maximum prison, suffering bouts of malaria.
He has denied prosecution allegations that he, along with three
Kampala men - Charles Berwanaho, a former police officer Bob Male Mugisha and Laba Kiwanuka - were part of a murder plot.
Mr Kiyingi was in Australia at the time of her murder.
Prosecutors allege the doctor paid a criminal gang and coordinated the killing by phone from Sydney.
He is accused of calling one of defendants a few minutes after the death and asking whether the mission had been successful.
The prosecution is expected to use phone call records to incriminate Mr Kiyingi.
High Court Judge Oscar Okumu Wengi will conduct the trial.
The case has fuelled months of media frenzy and has even been the subject of a local movie, Murder in the City, despite angry warnings from judges and defence fears that it could prejudice proceedings.