A phase II trial of concurrent cisplatin and 5-fluorouracil (5-FU) chemotherapy and radiation therapy (CT + RT) was conducted for the primary treatment of 12 patients with retrospective surgical FIGO stages III-IV squamous carcinoma of the vulva. Eight patients were stage III and four were stage IV. Chemotherapy was used as a radiation sensitizer and it was administered in two 5-day cycles 28 days apart. Cisplatin, 50 mg/m2/day iv on Days 1 and 2 or 100 mg/m2 on Day 1 or 2, plus continuous-infusion 5-FU, 1000 mg/m2/day for 4-5 days commencing on Days 1 and 28 of external-beam radiation therapy, are given. The pelvic radiation to a dose of 4400-5400 cGy is administered AP and PA to treat the primary tumor, the groin nodes, and the iliac vessels to the level below the common iliac nodes. Complete tumor responses were seen in 8 of 12 (67%) patients. Responses were observed in 6 of 8 (75%) stage III patients and 2 of 4 (50%) stage IV patients. Partial response were observed in 3 patients, and 1 patient had persistent disease. At the completion of concurrent chemoradiation therapy, radical vulvectomy or excision was used in 3 patients and posterior exenteration in 1. With a median follow-up of 37 months (range, 7-60 months), 10 patients are alive and free of disease, and 2 patients died at 12 and 15 months. There were no treatment-related deaths and no grade 4 toxicity. The morbidity included moist desquamation of the vulva in all patients, with grade 2 toxicity in 10 and grade 3 in 2. One patient had a deep venous thrombosis that responded to anticoagulation therapy. These data support the use of concurrent cisplatin and 5-FU chemotherapy and radiation therapy as an alternative to primary radical surgery to treat advanced-stage squamous carcinoma of the vulva.