The aim of study was to quantify the extent of set-up errors and to develop a quality assurance program using port films in Radiation Oncology Department, NCI, Cairo. It included 5 head and neck and 5 pelvic cancer patients for whom 108 films were taken. Film visibility was excellent in 62% and 68% of pelvic and head and neck films, respectively. Film rejection rates were 29% and 28% in the pelvis and the head and neck, respectively. The most common cause of film rejection was centering errors in pelvic films while in head and neck films, it was shielding errors.