The clinical syndrome of slowly progressive proximal limb and limb girdle muscular weakness and atrophy, or limb girdle syndromes (LGS), has a diverse aetiology. Several of the congenital, mitochondrial and other metabolic myopathies and spinal muscular atrophies are recently recognized causes of LGS. Thus the position of limb girdle muscular dystrophy (LGMD) as a discrete entity in the nosology of muscle disease deserves reappraisal. We have therefore reevaluated our experience of 33 patients in this light. Detailed clinical, electrophysiological, and pathological studies including autopsies in 2 cases, were performed. As a result we are confident that LGMD does exist as a sporadic or autosomal dominant (2 families) or recessive condition (2 families). There are therefore probably at least 2 distinct genotypes. Typical LGMD (18 patients in our series) is characterized by slowly progressive symmetrical proximal upper and lower limb girdle weakness and atrophy, elevation of the serum creatine kinase at some stage, dystrophic or less severe myopathic muscle lesions on biopsy, and myopathic EMG findings. Two minor subgroups of LGMD were identified in our series with similar clinical and laboratory features but distinguishable by the development of either facial (4 patients) or by distal limb muscle involvement (3 patients). A further group of patients with sporadic LGS (5 patients) had slowly progressive proximal symmetrical upper and lower limb-girdle weakness and atrophy with myopathic or neurogenic features on either EMG or muscle biopsy so that the precise characterization was difficult. Two of these patients had distal limb muscle involvement and contractures. One patient had upper limb-girdle muscle atrophy with normal lower limbs. A disorder affecting muscle, nerve or both remains a possibility in these cases.