The performance of 47 men was measured during a 16-week study. Eight of the men received placebos; nine received 1-methyl-Delta1-androstenolone acetate, an anabolic steroid; 15 received placebos and exercise; and 15 received the drug and exercise. There were no significant differences in strength, motor performance, or physical working capacity between the control and the androstenolone-supplemented groups. Differences in other factors such as vital capacity, limb circumference, and skin-fold thickness were also nonsignificant. Under the conditions imposed in this study there was no evidence that the anabolic steroid increased strength in young men. ergogenic drugs; strength measurements and physical working capacity under anabolic steroid therapy Submitted on December 14, 1964