A 38-year-old, homosexual, HIV infected patient, with diabetes mellitus, aortic prothesis and thrombocytopenia treated with corticosteroids presents a thoracic subcutaneous abscess with homolateral pneumonia. Diagnosis of nocardial infection due to N. asteroides is assured by the pus sample. There is apparently a primary pulmonary localization with secondary fistulisation in the subcutaneous tissue. Therapy consisting of imipenem and ofloxacin is rapidely effective. This is the first report of such a case in a HIV infected patient.