Polymyositis (PM) and dermatomyositis (DM) are inflammatory myopathic diseases that often accompany cancers. However, the relationship between PM/DM and acute myelocytic leukemia (AML) has not been elucidated. We present a case of PM that developed AML 12 months after initial diagnosis. We reviewed the cases in English literature and analyzed the association between PM/DM and AML. We conclude that PM/DM is a paraneoplastic syndrome of AML.