To evaluate the potential effect of androgens on human thyroid tumors, the incidence and distribution of cytosolic receptors for androgens were analyzed in thyroidectomy specimens from 31 patients. Fourteen specimens were from male and 17 from female patients. The specimens included five papillary carcinomas, five follicular adenomas, 15 colloid goiters, and six relatively normal thyroid tissues. All assays were performed by a protamine sulfate precipitation technique and analyzed by the method of Scatchard. Selected specimens were analyzed by sucrose density gradient. A receptor content greater than 1 fmol/mg cytosol protein was taken as positive if the dissociation constant was less than 1 nm. Seventeen of 31 specimens were positive for androgen receptors, with a dissociation constant of 0.26 +/- 0.09 X 10(-10) M and a receptor content of 11.20 +/- 4.77 fmol/mg cytosol protein. Four of five carcinomas, four of five adenomas, and nine of 21 benign thyroid tissues were positive for androgens. These androgen receptors are a single class with high affinity that are saturable and precipitate at the 6S (Svedberg unit) region similar to receptors in other androgen-dependent tissue. The data suggest that physiologic androgenic milieu may influence the growth of thyroid tumors.