To define the clinical, electrophysiological, and pathologic features of the myopathy associated with the use of HMG CoA reductase inhibitorsMethods.: Five patients with myopathy associated with HMG CoA reductase inhibitors were evaluated. Complete histories, physical examinations, manual muscle testing, serum creatine kinase, urine myoglobin measurements, electrodiagnoscic studies, and muscle biopsy were performed.