The 1839—1840 United States Senate election in New York was held on February 5, 1839 and January 14, 1840. Incumbent Senator Nathaniel P. Tallmadge was re-elected to a second term in office over scattered opposition.

Nathaniel Pitcher Tallmadge was an American lawyer and politician. He served two terms as United States Senator from New York (1833–1844) and was the 3rd Governor of the Wisconsin Territory (1844–1845).