Addressing the gathering, Yadav said his government was committed for the cause of people and improving the health sector was its priority.
The ambulances will service 21 districts.
"With today's addition total number of 433 ambulances are now available in 31 districts under (the) emergency medical transport services," an official said.
The facility can be availed free-of-cost by dialling 108. The ambulance service was launched with the help of private provider GVK.
Health minister Ahmad Hasan said that by December, 988 ambulances would be made available to the public.
Senior ministers Shivpal Yadav, Balram Yadav and officials of the government besides party workers were present on the occasion.
