A simple laboratory test for disclosure of peripheral androgen insensitivity has been suggested. The test is based on determination of sex hormone-binding globulin (SHBG) following single administration of testosterone preparation (Testoviron Depot, Schering, 2 mg/kg of body weight). The kinetics of SHBG response to exogenous testosterone was investigated first in a group of 5 healthy male volunteers. The highest highly significant decrease of SHBG level occurred 7th day after drug administration. The method of choice for SHBG determination is an immunoradiometric assay (IRMA). The test was used for a group of 15 children and young people suspected for androgen sensitivity disorder. In all cases, besides SHBG on days 0 and 7 testosterone, dihydrotestosterone and LH were measured, too. In three instances the response was negative: in the case of male Turner syndrome, with very low basal SHBG levels, in one case of confirmed diagnosis of testicular feminization and in the third case of suspected testicular feminization, which has not yet been concluded. In all other patients a significant decrease (in average to 62.8% of the basal level) was in agreement with clinical findings.