A 29-year-old man visited to our department with complaint of sudden onset multiple inflammatory papules and nodules on the face, chest, and back which appeared three months ago. There was no specific trigger without fact that he had been injected with testosterone enanthate (one of the anabolic androgenic steroids) 250mg intramuscularly 16 times every week to gain muscular strength. Based upon the clinical manifestation and history, we diagnosed him as acne conglobata induced by anabolic androgenic steroids. Anabolic androgenic steroids are well known for exerting direct and indirect influence on sebaceous gland and Propionibacterium acnes, consequently resulting in acne. They now have very limited medical indications, such as endocrinopathy, due to their systemic side effect like libido change, mood swings, and testicular atrophy, as well as dermatologic complication-acne.