Human gonads were examined for the presence of ir growth hormone-releasing-hormone. We demonstrated the presence of immunostainable cells both in ovarian and in testicular tissue using a non-crossreactive anti-GRH antiserum and the immunoperoxidase detection technique. In ovaries from ovulating women, GRH immunoreactivity was localized in the corpora lutea; granulosa cells, theca cells and cells of primary follicles did not stain. In premenopausal ovaries, staining was detectable in scattered luteinized stromal cells. In testes from post-puberal men GRH immunoreactivity was localized in the Leydig cells; cells of the germinal epithelium did not stain. These results demonstrate the presence of GRH in human gonads and suggest that this peptide may exert regulatory function at the testicular and ovarian levels.