Former Union minister and BJP vice president C P Thakur participated in the march which passed through the main streets of the capital.
Bihar Health Service Association President Ajay Kumar told reporters that their demands included regularisation of contractual doctors and parity of pays and allowance with Central government doctors.
Justifying the doctors demands, Thakur urged the state government to fulfill them.
The protesters included government as well private doctors.
The agitating doctors threatened to strike work from August 9 if their demands were not met.