In 1978 a Canadian archaeological mission conducted one season of excavation at the fire temple of Gach Dawar with the main focus of the operation on four ancillary rooms added to the exterior of the main Chahar Taq. The programme was terminated in 1979 by the onset of the Iranian revolution. The new excavation in 2007 re-examined the rooms originally exposed by the Canadian mission, as well as working in the heart of the Chahar Taq and other adjacent rooms. The discovery of a number of cult installations within the Chahar Taq explicitly indicates that the building was designed as a fire temple. The structural layout and the pottery recovered from the building imply an original construction dating to Sasanian times, four building phases identified. The presence of the Islamic material excavated can be explained as reuse of the building in subsequent periods.