A panel of federal judges says the new election district lines drawn by the Senate and Assembly majorities will be used in the fall elections.
The decision is a critical win for Senate Republicans hoping to secure their slim majority in the chamber despite a Democratic voter advantage of nearly 2-to-1 in the state.
Good-government groups have criticized the Senate GOP redistricting plan. They say it continues a tradition of twisting district lines to protect the power of the majority parties.
But the Senate Republicans have so far won all the state and federal legal challenges to the redistricting signed into law in March by Democratic Gov. Andrew Cuomo.
Senate Majority Leader Dean Skelos says Thursday the latest decision will allow an orderly election.
Senate Democrats had no immediate comment.