A case-control study of nasopharyngeal carcinoma was performed in Zagreb from 1989 until 1993. Blood selenium concentrations were determined in 34 patients with nasopharyngeal cancer and 47 normal subjects by means of the atomic absorption spectrophotometric method. The sera of nasopharyngeal cancer patients showed no significant differences in selenium values from the sera of normal individuals, but there were significant differences between patients with enlarged cancer (T4 stage) and normal individuals. The results suggest that lower blood selenium levels in this group of nasopharyngeal cancer patients may be a consequence of their disease, rather than the cause of the cancer.