A phase II clinical trial was initiated in 1987 to evaluate a new induction regimen of cis-platinum, 5-fluorouracil, and leucovorin (PFL) for patients with stages III-IV squamous cell carcinoma of the head and neck. Ninety patients were treated and followed for a median duration of 18 months. The median age was 55 and 87% of the patients had stage IV disease. The rates of complete and overall clinical response following three cycles of PFL were 57% and 80%, respectively; the rate of complete response at the primary site was 72%. Eighty-four percent of patients were treated to the primary site with radiation alone (median dose 68 Gy in daily 1.8-Gy fractions) irrespective of the location of the primary site or initial T-stage. The acute tolerance to full-course radiation following PFL was acceptable. The actuarial rate of primary site control for patients treated with radiation was 67% at 36 months. An important prognostic indicator for primary site control was a complete clinical response to induction PFL. For patients who achieved a complete response, radiation or surgery followed by radiation controlled primary site disease equally well at 70%. Patients with a partial response did less well. For these patients, surgery and radiation appeared slightly better than radiation alone.