Veterans Affairs was the leader in the 2013-14 fiscal year, devoting $103,694 of its approximately $3.5-billion budget to promoting tweets on one of its social media accounts.
Veterans Affairs Minister Julian Fantino wouldn't answer questions about the spending as he entered the House of Commons on Tuesday, telling one reporter that he was "just going to read notes on it."
A spokesman for Fantino said the money for the advertising didn't come out of the Veterans Affairs budget.
"It came from a central PCO [Privy Council Office] directed fund, that will be spent on departmental advertising somewhere if not at VAC," Nicholas Bergamini said in an email to CBC News.
The Privy Council is the administrative arm of government that works with the Prime Minister's Office.
CBC, BDC also paid for tweets
"As more and more Canadians turn to social media instead of traditional TV and radio, it is important that they too see and hear the remarkable stories of Canadian veterans," Bergamini said.
Veterans have complained about service cuts in the past year, and after one contentious meeting at which veterans said they felt disrespected Fantino was forced to apologize.
The Business Development Bank of Canada, or BDC, a Crown corporation, spent $99,129.63 on promoted tweets in 2013-14, though it spent by far the most on tweets of any department or Crown corporation the year before too: $68,059.57, for a total of $167,189.20 over two years.
BDC notes in the response to Liberal MP Geoff Regan's question that the final invoice for March 2014 isn't in yet.
The CBC, meanwhile, spent $77,291.67 "to purchase a combination of promoted tweets and a promoted account on Twitter," Rick Dykstra, parliamentary secretary to Canadian Heritage Minister Shelly Glover, noted in his response to Regan's written question.
A spokesman for CBC said using social media to connect with Canadians "ensures CBC's content stays top of mind in a changing media environment."
"The money was spent to promote the Sochi Olympics, Paralympics and NHL Revealed, all part of an overall advertising buy for our priority titles," Chuck Thompson said in an email.
The CBC and Radio-Canada are facing $130 million in budget cuts.