\s=b\ Twenty-two patients with squamous cell carcinoma of the head and neck were studied to assess potential abnormalities in total T lymphocytes, T4/T8 ratios, and natural killer cell function. Total T-cell counts were reduced for the entire group with the greatest reduction occurring in individuals with hypopharyngeal tumors and/or stage IV disease. Helper to suppressor ratios were within the norm for the total group, but specific site variances were detected in patients with oral cavity and hypopharyngeal primary carcinomas. Similarly altered T4/T8 ratios were noted with stage III disease. Substantive differences in natural killer cell activity were not observed. These data suggest that perturbations in T-lymphocyte subsets can be associated with decreased survival.