Three goalies, 12 defencemen and 20 forwards were named to the roster for the camp, set for August in Brossard, Que., and Lake Placid, N.Y.
MacKinnon is a strong possibility to be chosen first overall in the NHL entry draft on Sunday by the Colorado Avalanche. He and Drouin, who was named the Canadian Hockey League's player of the year in May, recently won the Memorial Cup with the Mooseheads.
They'll be joined at the camp by another draft-eligible Halifax teammate, goalie Zach Fucale.
The Moosehead trio are among eight players from the Quebec Major Junior Hockey League who received an invitation Friday. With the exception of Fucale, all are forwards.
Hockey Canada also invited 13 players from the Ontario Hockey League, 13 from the Western Hockey League and one player — Michael Matheson of Boston College — from the NCAA.
Of the 35 roster players, 19 are eligible for Sunday's NHL draft, including Max Domi of the OHL's London Knights.
Fourteen others were chosen last year, among them Toronto Maple Leafs prospect Morgan Rielly of the WHL's Moose Jaw Warriors and New York Islanders draft pick Griffin Reinhart of the Edmonton Oil Kings, also of the WHL.
Selection camp in December
Reinhart's younger brother Sam Reinhart, of the WHL's Kootenay Ice, is not draft-eligible until 2014. Connor McDavid of the OHL's Erie Otters, at age 16 the youngest player named to the roster, is not eligible until 2015.
The August camp will feature exhibition games against Finland, Sweden and the United States.
A selection camp in December will determine the 22 players who will represent Canada at the 2014 IIHF world junior championship in Malmo, Sweden.
It was announced on Wednesday that Brent Sutter of the WHL's Red Deer Rebels will be Canada's head coach. His assistants will be Benoit Groulx of the QMJHL's Gatineau Olympiques and Ryan McGill of Kootenay.
Sutter has never lost a game in two stints as Canada's world junior coach, capturing consecutive gold medals in 2005 and 2006.
But Canada has not won gold at the tournament since 2009.
Griffin Reinhart, Rielly, MacKinnon and Drouin all played in the most recent world junior championship in Ufa, Russia, where Canada finished a disappointing fourth.