Finance Minister Jim Flaherty says the negative numbers reflect the impact of the global economic crisis on government finances, as well as stimulus measures aimed at stabilizing the country's economy.
The federal deficit is expected to hit $56 billion by the time the fiscal year ends March 31.
The numbers compare to a $300-million surplus for the month of December 2008 and a $400-million surplus through the first three quarters of the last fiscal year.
Mr. Flaherty says more than $16 billion of this year's deficit is attributable to stimulus measures under the government's Economic Action Plan - including tax reductions, enhanced EI benefits and support for the automotive industry.
Revenues were down $19.4 billion - or 11.2 per cent - through the third quarter, while program expenses were up $22 billion, or 14.8 per cent.
Public debt charges dropped $1.7 billion on a year-over-year basis due to lower interest rates.
