A judge in Peterborough delivered the sentence Thursday, which also includes 18 months probation.
Del Mastro has filed an appeal of his October conviction. He's expected to ask for bail pending the outcome of that appeal.
The former MP was found to have exceeded spending limits, failed to report a personal contribution of $21,000 to his campaign, and knowingly submitted a falsified document.
On his way into court Thursday, Del Mastro was asked if he's prepared to serve time.
"I'm prepared to do whatever is necessary to stand for the truth," he told reporters.
Del Mastro, 44, was once Prime Minister Stephen Harper's point man defending the Tories against allegations of electoral fraud. He maintained his innocence and called the verdict the judge's opinion.
Del Mastro 'effectively fined himself': lawyer
At a pre-sentencing hearing in April, he choked back tears as he described the "nationwide condemnation" he had to endure as a result of the charges.
"There are some who would appreciate an opportunity to hold a public stoning in the town square," he told Justice Lisa Cameron. "It's my hope that the significant consequences that I have endured and shared will be considered in your deliberations."
The prosecution called for up to 12 months in jail, while the defence asked Cameron for a conditional discharge or, at most, a fine.
Del Mastro resigned his Peterborough seat in the House of Commons — where he had been sitting as an Independent since being charged — shortly after his conviction.
His lawyer, Leo Adler, argued his client's resignation was "for the good of the community."
"Mr. Del Mastro, by resigning, effectively fined himself," Adler said in April. "That's the real penalty Mr. Del Mastro incurred."
The Crown, however, argued Del Mastro had refused to accept his convictions and shown no remorse for what it called a intentional and extensive efforts to "conceal the deception."