A hydroxylapatite assay was used to assay androgen receptor levels in 23 primary laryngeal carcinomas, nine metastatic laryngeal carcinomas, and three oropharyngeal carcinomas. The median androgen receptor level in laryngeal carcinoma was 0.7 femtomoles of receptor protein per milligram of cytosol protein. Ten patients with advanced or metastatic laryngeal carcinoma and one patient with metastatic floor of mouth carcinoma were treated with the antiandrogen flutamide. There were three short-lived partial responses (1, 2, and 2.5 months) in nine patients whose tumors could be evaluated for response. Toxic reactions consisted of mild breast tenderness, and hypercalcemia in two patients with bone metastases. Androgen receptor levels did not correlate with response to flutamide. The low androgen receptor levels in laryngeal tumors may account for the relative inactivity of the antiandrogen in laryngeal cancer.