Fifty-six untreated patients with inoperable squamous cell carcinoma of the head and neck were treated with carboplatin 70 mglm2i.v. daily on days 1-5 and 29-33 in combination with simultaneous conventional radiation up to a target volume dose of 50 Gy. Depending on tumor response and upon recommendation of surgeons, 21 of 56 patients underwent surgery after a radiation dose of 50 Gy and two courses of carboplatin. Patients who showed pCR after surgery received no further radiotherapy. In all other patients radiotherapy was continued using a shrinking field technique up to a target absorbed dose of 70-74 Gy. Combined modality induced 66% complete remission (CR) and an overall response rate of 98%. After completion of the whole treatment program (combined modality±surgery) 53 (94%) of the 56 patients were disease free. The median survival for all patients is 25+ months and the percentage of two-year survivors is 53%. Myelosuppression was the most frequent toxicity, but rarely was severe; leukopenia and thrombocytopenia of WHO grade 3 occurred in 21% of the patients. No other toxicities above WHO grade 2 occurred. Nephrotoxicity, neurotoxicity and ototoxicity were not seen. The addition of carboplatin did not increase the rate of surgical complication over that expected for preoperative radiotherapy. Two patients died of pulmonary embolism after surgery. Combined modality with carboplatin and simultaneous radiation is a highly active and well-tolerated regimen for untreated patients with inoperable squamous cell carcinoma of the head and neck.