The endorsements come after more than 400 delegates and their guests gathered at the Hilton Hotel in Hartford for the two-day political convention of the union federation.
Blumenthal, Malloy and Republican gubernatorial candidate Tom Foley addressed the convention.
AFL-CIO officials said Republican U.S. Senate candidate Linda McMahon was invited to address the convention, but did not respond to the invitation.
A spokesperson for McMahon said the campaign did not have a record of the union contacting them.
"We have a pretty organized system, and this is one event that we would have been particularly eager to attend," Shawn McCoy, deputy communications director for the campaign said in an e-mail.
“This election is extremely important because the economic crisis in this country is putting the American dream in jeopardy,” John Olsen, President of the Connecticut AFL-CIO, said in a news release.
During the convention, delegates reviewed, debated and voted on endorsement of candidates for office. The union represents 225,000 union members in the state.