Two androgens (testosterone, 5 alpha dihydrotestosterone) were measured by radioimmunoassay in the seminal liquid. A statistic comparison of the results has been applied to samples taken from sterile men and classed chiefly according to sperm count. Different groups were explored: normospermia; oligospermia; various azoospermias. No significant differences in testosterone were found between the groups. Levels of DHT are lower in oligospermia, and much more in azoospermia. The signification of the results is discussed.