Salivary testosterone levels were measured in 18 normal men, 29 oligospermic and six azoospermic subjects, using a specific and sensitive radioimmunoassay (RIA). There was a significant reduction (P less than 0.001) in salivary testosterone levels in the group of oligospermic (0.266 +/- 0.086 nmol/l) and azoospermic (0.234 +/- 0.055 nmol/l) subjects when compared with controls (0.348 +/- 0.070 nmol/l). A good correlation was found between salivary and plasma testosterone levels in normal (r = 0.62, P less than 0.01) and infertile men (r = 0.58, P less than 0.01). This study demonstrates that salivary testosterone levels, a non-invasive means of sample collection, may be used for evaluation of androgen status in male infertility.