“I am proud to endorse my friend @SenGillibrand to be our next President and the nation’s first woman President,” Maloney wrote on Twitter.
“I saw her tenacity when we fought together to pass the 9/11 Health bill and know she has what it takes to defeat Trump.”
Gillibrand officially announced her 2020 candidacy on Sunday after having formed an exploratory committee in January.
The 52-year-old New York lawmaker joins a crowded and diverse pool of Democratic candidates vying to take on President Trump in 2020. She is one of six women who have announced runs so far.
Maloney’s endorsement is Gillibrand’s first so far from a sitting member of Congress, according to Politico.