The country's new defence minister released the figure Monday night, and it is the estimated incremental cost for the current mission, which began last fall.
Jason Kenney says he'll be tabling the figures in Parliament this week, but they shouldn't be taken as the last word.
He said in a statement the costs will ultimately be higher than that, "but how much higher will depend on whether we wrap up the operation at the end of March, or extend it, so total final costs are still difficult to calculate."
But to date Kenney says the "hard costs we are incurring are $122 million, which will be reflected in the estimates," which the government is obliged to table as part of its regular reporting to Parliament.
The figures reflect what is being spent in the current budget — or fiscal — year on the CF-18 bombing campaign, which is based out of Kuwait, and the deployment of special forces troops who are training Kurdish peshmerga forces in northern Iraq.
"We think these costs are entirely reasonable given the importance of this mission where Canadian Special Operations and our Royal Canadian Air Force are having a meaningful impact against this genocidal terrorist organization, the so-called 'Islamic State.'" Kenney said in a statement.
To this point, the government had refused to say what it believed the costs might be, and the release comes one day ahead of an expected report by the parliamentary budget office, which has done its own calculation.
How much it may differ from the government's estimate remains to be seen.
It was the opposition NDP who asked the budget watchdog to crunch the numbers after weeks of stonewalling by former defence minister Rob Nicholson.
Both New Democrats and Liberals have complained that other countries, notably the United States, release running tallies on how much their military missions against the Islamic extremist organization costs.
According to government sources on Monday, part of the reluctance to talk about Iraq costs related to the controversy that erupted for the Harper government during the Libya bombing campaign when former defence minister Peter MacKay's estimate of $50 million turned out to be wildly off the mark.
The incremental pricetage for that mission ended up being $103.6 million, according to figures released months after the campaign ended.
The figure, like all defence estimates, represents the incremental cost — the amount of money the department spends over and above the routine expense of maintaining an army.