A 20-year-old male with asymptomatic inherited type 1 antithrombin deficiency and a family history of thrombosis started injecting himself with testosterone 250 mg intramuscularly twice weekly for 5 weeks. He presented to the hospital with progressive dyspnea on exertion, chest pain and hemoptysis. Workup revealed bilateral submassive pulmonary embolism and proximal right lower extremity deep vein thrombosis. He was treated with intravenous (IV) unfractionated heparin and underwent catheter-directed thrombolysis with alteplase to the main pulmonary arteries. Postprocedure, he remained on IV alteplase infusion for 24 h and unfractionated heparin in the intensive care unit. Concomitantly he received plasma-derived antithrombin concentrate. He was transitioned to subcutaneous enoxaparin twice daily and discharged from the hospital on oral rivaroxaban 15 mg twice a day. This case highlights the heightened thrombogenic effect of anabolic steroids in the setting of underlying thrombophilia especially in younger subjects.