He is believed to have drowned on Tuesday afternoon while on holiday with his family in Miami.
"Canada and the world have lost a great scientist and a great man", Julio Montaner of the British Columbia Centre for Excellence in HIV/AIDS told The Globe and Mail.
Wainberg was the founder and director of McGill University's AIDS Centre alongside a professor of medicine and microbiology and immunology.
He was best known for identifying 3TC (Lamivudine) as one of the first effective anti-viral treatments that helped extend the survival of HIV/AIDS patients nearly indefinitely. Later, he also published some of the earliest research on the effectiveness of antiretroviral cocktails.More news: Microsoft Tests Steam-Style Refunds For Xbox One
But Wainberg did not limit himself to lab work, becoming an advocate for more available and affordable HIV/AIDS treatment and destigmatizing those living with the disease.
The TAC said Wainberg, a former President of the International AIDS Society, was also an outspoken critic of former president Thabo Mbeki and Health Minister Manto Tshabalala-Msimang's AIDS denialism.
Wainberg would have turned 72 on April 21. He also extensively researched HIV drug resistance to identify mutations that caused some medications to not work as effectively. "Mark Wainberg was a giant in HIV science", Michel Sidibé, executive director of UNAIDS, said in a press release. Wainberg was transported to a local hospital where he later died. His ensuing AIDS research earned him honors such as the Order of Canada and the Legion d'honneur, the highest honors for civilians given by Canada and France, respectively. It is unclear if he died from drowning or another reason.
A friend of, and informal adviser to, UNAIDS for many years, he also served as the President of the International AIDS Society from 1998 to 2000.