Scleromyositis is a new clinical entity, an overlapping syndrome involving two distinct autoimmune diseases, systemic scleroderma and polymyositis or dermatomyositis. We report an observation of a 43-year-old female patient with a history of thyroidectomy, who has been presenting with phonation and swallowing disorders for over 6 months. Clinical examination revealed neuro-myogenic syndrome. Biological findings included elevated creatine phosphokinase at 1497 IU/L and lactate dehydrogenase at 954 IU/L, and the presence of a chronic inflammatory syndrome on serum protein electrophoresis. The electroneuromyography showed sensitive and motor polyneuropathy associated with polymyositis. Immunological tests revealed positive anti-PM/Scl-75 antibodies in the DOT myositis assay. The patient was treated with corticosteroid therapy 1mg/kg/day plus adjuvant plus methotrexate 15mg/week. The evolution was marked by a progressive clinical improvement of the motor deficit and biological improvement with a clear decrease in creatine phosphokinase.