Local control of advanced pelvic malignancies, particularly when complete surgical resection is not feasible, is often impeded by dosage limitations in radiation therapy and the intolerance to radiation of normal tissues. This is a preliminary report on the feasibility of improved local control in pelvic malignancies treated by intra-operative radiation therapy, as a radiation boost, in addition to conventional surgical resection and external beam radiation therapy. Fifteen gynaecological malignancies (five cervix, five uterus, four ovary, and one vulva) from Rush Medical College and the University of Navarre, as well as 36 other pelvic malignancies (32 colorectal, 4 genito-urinary) from Rush Medical College were reviewed. All tumours were advanced or recurrent, and all patients were felt to be at high risk of local failure. IORT was administered at a dose range of 10-26 Gy. Our data suggest that the probability of local control improves when IORT is used for primary and for microscopic disease, when the tumour is at least partially resectable, and when the total dose given in IORT and external beam radiation exceeds 70 Gy.