The duo, posted at police stations in Mumbai, were on their way back home after work when the mishap took place, Nargoli assistant police inspector Vijay M Kare said.
At around 1.30 AM, while the two policemen were passing near the Ovli dhabha between Bhiwandi and Kalyan, a car coming from behind rammed into the bike, as a result of which the duo fell down.
They were rushed to a hospital where constable - Sanjay Baban Munde (40) - was declared dead while the other victim was being treated at a private hospital, police said.
Investigation was on to trace the car which hit the bike, police added.