His wife Mila and the couple's four children watched as eight Royal Canadian Mounted Police officers in bright red ceremonial uniforms carried the coffin into a government building opposite Parliament.
Prime Minister Justin Trudeau, dressed in a black suit, later stood in silent tribute to a man he had praised as "one of the lions of Canadian politics". He crossed himself and tapped the coffin before signing the book of remembrance.
Mulroney will lie in state until 1 p.m. EDT (1700 GMT) on Wednesday, when his body is due to be transported to Montreal for a state funeral on Saturday.
A corporate lawyer turned businessman, Mulroney led the center-right Progressive Conservatives to a historic win in 1984 and served for almost nine years as prime minister.
Highlights of his tenure included a free trade deal with the United States and the introduction of a goods and services tax, which although unpopular helped fix the government's finances.
"He loved this country with his whole heart, and he knew we were capable of great things," Trudeau told legislators on Monday during a special session to pay tribute.
(Reporting by David Ljunggren in Ottawa; Editing by Nia Williams)
