The two were found dead after police responded to a medical call just before noon at their home in an affluent section of northeast Toronto.
He declined to release the age of the victims, where they were found in the house, whether a weapon was recovered, whether the bodies showed signs of trauma, and who found the bodies.
Mr Sherman founded the Apotex in 1974 and stepped down as chief executive in 1974.
According to Forbes, Sherman, 75, was the 12th richest man in Canada and ranked 660th among world's billionaires, with an estimated net worth of $3.2 billion, as recorded in March 2017. "We'll have more information tomorrow after the post mortem examinations".
Detective Brandon Price told Canadian broadcaster CBC that investigators were still trying to determine if there was foul play involved.
Police did not say who made the call, while the National Post reported that the bodies were initially discovered by a real estate agent, who came to the couple's luxury mansion, which is now up for sale. However, today, the company employees more than 10,000 workers as Apotex has transformed into one of Canada's largest pharmaceutical companies.
Ontario's health minister, Dr. Eric Hoskins, said the couple had been discovered dead. The pharmaceutical company produces and exports generic drugs to more than 115 countries. Those include manufacturing and research facilities concentrated in the Toronto area as well as in Winnipeg.
"I have had the privilege of knowing them both for many years", said Mr Tory.
"Wonderful human beings, incredible philanthropists, great leaders in health care", he wrote.
Sherman's wife, Honey, was a member of the board of the Baycrest Foundation and the York University Foundation. She also served on the boards of Mount Sinai's Women's Auxiliary, the Simon Wiesenthal Center and the International American Joint Distribution Committee.
Toronto Mayor John Tory said in statement he was "shocked and heartbroken" to learn of the deaths, noting that the couple had made extensive contributions to the city.
The Shermans made numerous multimillion-dollar donations to hospitals, schools and charities and had buildings named in their honor. Neighbours confirmed that the property was the couple's home. They also had close ties to the Jewish community as they donated roughly $50 million to the United Jewish Appeal - a Jewish philanthropic umbrella organization that later changed its name to the Jewish Federations of North America.
The Shermans recently listed their home for sale for almost 7 million Canadian dollars, about $5.4 million.
Sherman was born in Toronto, Canada in 1942 and was the youngest to ever enter into the University of Toronto's Engineering Science program at age 16.