The upper house will see 18 members of each party when the new legislature is sworn in after the first of the year, the first time the state Senate will be split since 1893.
"As of today officially there's no longer a majority party in the state Senate," said Len Fasano, a Republican who has been serving as the Senate minority leader for two years. "We now are a chamber of equals. The old way of doing things is gone."
They needed to win four seats to regain the majority for the first time since 1996. Democrats currently control the 36-member chamber by a margin of 21-to-15 seats. Lt. Governor Nancy Wyman, a Democrat, will vote in situations where there is a tie.
"We have equal voice, equal power, and equal policy making," Fasano added.
Democrats maintained control of the state House, but have the slimmest margin in decades.
Dr. William Petit, whose wife and two daughters were killed in a notorious 2007 home invasion, declared victory in his bid for a seat in the state House.
Voter turnout was brisk Tuesday. Secretary of the State Denise Merrill said turnout could exceed the 70-to-75 percent that's typical for presidential elections.