We present a case of polymyositis (PM) following intrauterine fetal death. The first presentation of PM in the patient was during postpartum. The patient was referred to our hospital because of a fever of unknown cause 13 d after delivery of dead fetus at 32 weeks' gestation. PM was diagnosed based on the increased serum creatine phosphokinase level, typical electromyogram findings and characteristic muscle biopsy findings.