Police say Tesfaye Asefa was last seen just after 10 a.m. on Monday in downtown Toronto.
They say Asefa has been held at a psychiatric facility since he was found not criminally responsible for two counts of sexual assault in 2011.
Police say he should not be approached and anyone who sees him should call 911.
Asefa was previously reported missing from the same area in August 2018 and May of last year.
A number of recent incidents involving escaped patients prompted a prominent Toronto psychiatric hospital to review its processes around patient passes last year.
The Centre for Addiction and Mental Health said in December it will implement all recommendations made by the external panel that conducted the review.
The facility’s president, Catherine Zahn, also vowed to build new infrastructure and communicate more often with police, adding the institution has already begun making changes.
The panel made 12 recommendations after several patients escaped from the hospital’s forensic facility, which treats people found not criminally responsible for violent crimes.
Zhebin Cong escaped in July of last year and fled to China after he was found not criminally responsible for the second-degree murder of his roommate.
That same month, Ahmed Sualim went missing from the psychiatric hospital and was located hours later. Sualim was found not criminally responsible in a series of violent robberies.
Another man found not criminally responsible for aggravated assault escaped from the same institution in November and was found by police the next day.
Later in November, a man found not criminally responsible for assault with a weapon and possession of a weapon escaped the hospital. He was found and returned within 24 hours.
The provincial government said it welcomed the report and would review its findings.