Thirty-eight patients with advanced, inoperable squamous cell carcinoma of the head and neck were randomized to receive methotrexate alone or methotrexate with Bacillus Calmette-Guérin. The response rates with methotrexate (3 of 19) and methotrexate plus B. Calmette-Guérin (4 of 16) were similar, as was the duration of response and survival of the two groups. The results of in vitro immunological studies of lymphocytes were assessed. Marked weight loss, poor performance status, and distant metastases were the most important prognostic factors. The presence of anergy was significantly correlated with weight loss. This study also indicated that a large tumor burden is a frequent occurrence in advanced head and neck cancer and may account for the lack of efficacy of B. Calmette-Guérin.