The mishap took place around 2.30 am when the duo was travelling on the two-wheeler during night patrolling and were hit by the tanker, police said.
They were rushed to a hospital where the constable Sukhchand, a resident of Todabhim in Dausa district, was declared dead while the jawan Meghraj is stated to be in a critical condition.
The constable was posted with Jawahar circle police station. The body has been handed over to the family members after postmortem, police said, adding that the tanker fled from the spot and a hunt is on for him.