Idiopathic inflammatory myopathies are systemic, autoimmune diseases characterized by proximal symmetrical muscle weakness. We review the myositis-associated and myositis-specific autoantibodies, among them the anti-SRP autoantibody. Among those autoimmune myopathy cases, that are associated with autoantibodies, we can detect anti-SRP autoantibody positive myositis cases. We describe the role of signal recognition particle, its structure and role in protein biosynthesis. We review how necrotizing autoimmune myopathy is identified, and the differences from classical polymyositis. The anti-SRP titer correlates with disease activity. We present some cases to show how the disease appears in childhood and also some rare cases from the literature. Finally we present a case to draw attention to the importance of this disease.