Dermatomyositis is a type of inflammatory myopathy characterized by inflammatory and degenerative changes of the muscles and skin. The paraneoplastic dermatomyositis is a subtype associated with cancer. The pathophysiothogy remains unfully understood. The diagnosis is supported by both the clinical and serological features. The treatment involves both the DM and the malignancy. Multi-disciplinary management is fundamental for patients. However the pronosis remains usually poor. We report a case of paraneoplastic dermatomyositis revealing an ovarian cancer, the purpose is to illustrate the diagnostic, therapeutic and pronostic of this entity.