High quality reprint of this recently declassified 1970 study. United States and South Vietnamese forces entering Cambodia on 1 May 1970 seriously weakened the enemy posture as they captured large quantities of his supplies and inflicted heavy casualties on Viet Cong/North Vietnamese Army forces operating in Cambodian sanctuaries. This movement of troops supported by airpower is profiled here in "The Cambodian Campaign, 29 April - 30 June 1970," a special CHECO Report, as one of the most significant actions of the Southeast Asia conflict. The quantity of supplies contained in the caches captured in Cambodia during May - June 1970 exceeded the total supplies contained in all the caches captured in RVN for the 15 months from February 1969 through April 1970. Airpower was employed in two ways in the Cambodian campaign; first, in tactical air support of friendly ground operations and second, in an interdiction campaign. The interdiction campaign consisted of three phases: (1) a period of limited interdiction in northeastern Cambodia; (2) an extension of interdiction in northeastern Cambodia; and (3) a retrenchment back to a limited area. The establishment and development of the air interdiction campaign and tactical air and ARC LIGHT missions in support of the operations in Cambodia are detailed in this report, along with a statistical summary of airlift operations.