TREATMENT of hypogonadism in males has been carried out with testosterone propionate and with methyl testosterone. The pure steroid, testosterone, has been used also in pellet form by implantation. Recently aqueous suspensions of estrogenic steroids have been employed in treating women in the climacteric. A trial of a similar suspension of pure testosterone was undertaken. The preparation used contained 20 mg. testosterone in 1 cc., and was furnished in sealed glass ampoules.2 Prior to removal into the syringe for intramuscular injection the content of the ampoule was agitated vigorously by hand to assure a uniform suspension. No pain was experienced by the patients, and no local reactions were observed. Patients learned with ease to make their own injections. The results are illustrated herein by reports of a series of five men who were treated for hypogonadism due either to a delayed development or to the climacteric. Case 1, D.F., Wis. Gen. Hosp. No. 126402, aged 18, was referred because of delayed adolescent development which had led to his rejection by the Selective Service Board.