Both sides struggled to play football on a bumpy pitch, and chances were few and far between on a bitterly cold day.
Ayr's best chance of a poor first half fell to skipper Raymond Logan who headed a Paul Weaver cross wide of goal when he should have done better.
But United failed to press on after their bright start, and the game was bogged down in midfield.
It took Raith until the second half to threaten when Steven Bonar and Iain Davidson both headed wide.
Ayr threw on joint top scorer Gareth Wardlaw for the closing stages and they looked more of a threat in front of goal.
Wardlaw almost grabbed a winner, but saw his powerful shot saved before Dougie Ramsey lashed the rebound wide.
Raith had a good late chance of their own when Mark Crilly fired wide from close range to sum up a bad afternoon.