Six members of a family suffered from benign myopathy over four generations. The clinical, laboratory, electromyographic, histological and genetic data were consistent with benign myopathy with autosomal dominant inheritance. Congenital torticollis was a feature in one patient. Linkage studies revealed no linkage between the locus of this myopathy and the locus of any of 17 genetic markers investigated. This family was of Polish descent, which indicates a widespread occurrence of this benign hereditary myopathy. The data presented are a strong argument in favor of a specific new disease entity.