A 42-year-old Mexican migrant laborer with a previous history of neurofibromatosis presented with a stuffy nose and chronic ulceration of his soft palate. Multiple subcutaneous nodules were found on his skin, and laboratory investigation revealed an elevated activated partial thromboplastin time (APTT). Further laboratory evaluation showed a lupus-like circulating anticoagulant deemed IgM by quantitative immunoglobulin studies. Although coagulation defects in lepromatous leprosy are rare, the preoperative preparation of a patient with leprosy may require a screening prothrombin time (PT), APTT and platelet count. Abnormalities in these values may indicate the need for specific factor assays and a search for circulating anticoagulant.