Inflammatory myopathies (IM) is a rare inflammatory muscle disorder, which can be broadly divided into 5 subgroups. The accurate diagnosis of subtype of IM can be challenging due to a diverse presentation of the disease. On the other hand, skeletal muscle complication is common in patients with systemic lupus erythematosus (SLE) in the form of myalgia or myopathy. Inflammatory myopathy is a rare association of SLE and the diagnosis and treatment can be quite challenging. A 43-year-old lady with underlying systemic lupus erythematosus (SLE), presented with subacute onset progressively worsening muscle weakness involving upper limbs and lower limbs. Neurological examination showed findings consistent with proximal myopathy, with proximal power of 3/5 and distal power of 4/5. She has elevated creatinine kinase, ALT and AST level. Her myositis-specific autoantibodies were positive for anti-Ku antibodies. Her electromyography showed evidence of active myopathy of the upper and lower limb. Here, we would like to report a case of polymyositis in a patient with SLE.