Here we report a case of pulmonary embolism. He has myelodysplastic syndrome and suffered from anemia and thrombocytopenia. Methyl-testosterone was therefore added in the regimen for 23 months. However, this patient presented to emergency department as syncope and hypoxemia. Computed tomography confirmed the emboli in the pulmonary arteries. In patients with relative symptoms, the use of testosterone and other anabolic-androgenic steroids should arouse the alertness of thromboembolism event.