During the Shah's reign Iran purchased roughly 96 CH-47 Chinooks for the IIAF (Imperial Iranian Air Force), another 50 were ordered (one of the many weapons the Shah had ordered and paid for which were never delivered to the new regime) but were withheld following the Iranian Revolution.
During the war with Iraq in the 1980's at least 8 Chinooks were lost.
On one fateful day, 15 July 1983, an Iraqi Mirage F-1 destroyed three Iranian CH-47s flying low to deliver marines to a front line.
It's been rumored that Iranian Helicopter Company completely overhauled, re-built and reverse-engineered some models of all military helicopters including the Chinooks.
As of December 2001, the IRIAF (air force) was operating 14 CH-47Cs, including 5 completely re-built from the war. 6 others have been transferred to the Revolutionary Air Guard, "Gordane-Pasdaran" which was a separate force controlled by the air force.