Rep. José Serrano revealed Monday that the has Parkinson’s Disease — as he announced he won’t seek another term in 2020.

“Although the disease has not affected my work in Congress, over the last few months I’ve come to the realization that Parkinson’s will eventually take a toll, and that I cannot predict its rate of advancement,” the Bronx pol said in a statement.

“I pledge to my constituents that I will be here fighting until may last day in office and beyond.”

Serrano was facing a Democratic primary challenge from City Councilman Ritchie Torres.

The 75-year-old congressman has held his Washington office since 1990.