Since Mr Blagojevich was arrested last month, he has persistently denied the charges against him and has refused to resign.
There is no trial date set in the criminal case.
"If I thought I had done something wrong I would have resigned in December," he told senators.
"I didn't resign then and I'm not resigning now because I have done nothing wrong."
He says he is the victim of a political vendetta.
If he is found guilty of abusing his power he will be forced from office. Senators are expected to vote later on Thursday.
Impeachment prosecutor David Ellis, in his rebuttal, emphasised that Mr Blagojevich had refused to appear under oath to answer questions, opting instead to make a closing speech.
In his closing remarks, Mr Ellis said: "The evidence showed that throughout his tenure as governor, the governor has abused the power of his office and put his own interest above the interest of the people."
The impeachment motion was passed by 114 votes to one in the House of Representatives on 9 January, although only 60 votes were needed.
The impeachment follows an investigation by a 21-member committee of Illinois legislators, which looked at testimony from FBI agents who wiretapped phone calls to and from the governor's office about who should fill President Obama's seat.
It is alleged the conversations show that Mr Blagojevich was trying to use the seat to get himself or his wife a job.
The panel said the evidence showed Mr Blagojevich was not fit to be governor, and voted unanimously to proceed to an impeachment vote.
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