Islam was rescued from Salkosa, in the trijunction of Kokrajhar, Bongaigaon and Dhubri districts in lower Assam late last night, the police said.
Islam and his colleague Gadapani Pathak were kidnapped on May 2 by four unidentified armed men at Kakragaon while they were returning to Guwahati from Dhubri in a car.
Both Pathak and Islam were engineers in agriculture engineering department and based at Gauripur in Dhubri district.
Pathak, a superintendant engineer of Agriculture department, was shot dead by the kidnappers. His body was recovered a day later from Baitamari in Abhayapuri.
While Islam was rescued yesterday night, the news was made pubic only this morning.
The details of the rescue operation were yet to be made public.
The engineer was admitted to a local hospital in Bongaigaon.
Islam's health had deteriorated during his days in captivity, the police said.
