Idiopathic inflammatory myopathies are systemic autoimmune diseases characterized by symmetrical proximal muscle weakness. One of them is the subgroup of necrotizing autoimmune myopathy, which has recently been recognized as a separate entity. In addition to the typical symmetrical muscle weakness, it is characterized by very high creatine kinase levels, myopathic triad in the electromyography, and myocyte necrosis without significant inflammation. The paper aims to review this rare entity, which has to be diagnosed and treated quickly in every case.