OBJECTIVE To determine the feasibility of using preoperative chemoradiotherapy to avert the need for more radical surgery for patients with T3 primary tumors, or the need for pelvic exenteration for patients with T4 primary tumors, not amenable to resection by standard radical vulvectomy. METHODS Seventy-three evaluable patients with clinical Stage III-IV squamous cell vulvar carcinoma were enrolled in this prospective, multi-institutional trial. Treatment consisted of a planned split course of concurrent cisplatin/5-fluorouracil and radiation therapy followed by surgical excision of the residual primary tumor plus bilateral inguinal-femoral lymph node dissection. Radiation therapy was delivered to the primary tumor volume via anterior-posterior-posterior-anterior (AP-PA) fields in 170-cGy fractions to a dose of 4760 cGy. Patients with inoperable groin nodes received chemoradiation to the primary vulvar tumor, inguinal-femoral and lower pelvic lymph nodes. RESULTS Seven patients did not undergo a post-treatment surgical procedure: deteriorating medical condition (2 patients); other medical condition (1 patient); unresectable residual tumor (2 patients); patient refusal (2 patients). Following chemoradiotherapy, 33/71 (46.5%) patients had no visible vulvar cancer at the time of planned surgery and 38/71 (53.5%) had gross residual cancer at the time of operation. Five of the latter 38 patients had positive resection margins and underwent: further radiation therapy to the vulva (3 patients); wide local excision and vaginectomy necessitating colostomy (1 patient); no further therapy (1 patient). Using this strategy of preoperative, split-course, twice-daily radiation combined with cisplatin plus 5-fluorouracil chemotherapy, only 2/71 (2.8%) had residual unresectable disease. In only three patients was it not possible to preserve urinary and/or gastrointestinal continence. Toxicity was acceptable, with acute cutaneous reactions to chemoradiotherapy and surgical wound complications being the most common adverse effects. CONCLUSIONS Preoperative chemoradiotherapy in advanced squamous cell carcinoma of the vulva is feasible, and may reduce the need for more radical surgery including primary pelvic exenteration.