Polymyositis (PM) and Dermatomyositis (DM) are autoimmune myopathies characterized by inflammation and weakness of proximal muscles with extra muscular manifestations. In DM there is muscle weakness associated with skin rash. Although both these disorders share some common clinical and histological features like muscle weakness, inflammatory infiltrates on muscle biopsy, but they have certain differences both in terms of presentation and patho-physiology. Involvement of skin is the primary clinical feature, which distinguishes DM from PM.