• We describe a case of limb girdle muscular dystrophy with associated myasthenia gravis. This association has not been previously noted in the literature. The unusual feature of the case was that symptoms coexisted for several years before a correct diagnosis was made. The diagnosis was based on the clinical picture and the results of the muscle biopsy and electrophysiologic testing. This case serves to illustrate the fact that a separate problem should be considered when the clinical picture is not compatible with the underlying diagnosis.