Myositis of the skeletal muscle is a rare complication of inflammatory bowel disease. We report about a 33-year-old woman with quiescent ulcerative colitis known since 1995. She had suffered from recurring fever and pain in the thighs for about 4 weeks. Electromyography of quadriceps and deltoid muscles revealed myopathic changes. Diagnosis of polymyositis was confirmed by magnetic resonance imaging indicating edematous changes in the distal extremity muscles. The symptoms rapidly responded to high doses of steroids. Review of the literature indicates only a few cases describing an association of ulcerative colitis and myositis, most of them during acute exacerbations of the disease. In contrast, the present patient was in remission. Diagnosis of myositis should be considered in inflammatory bowel disease patients complaining of myalgia or muscular weakness. Magnetic resonance imaging may show specific features and can be used in addition to laboratory investigations and muscle biopsy for diagnosis of polymyositis.