Four patients with typical signs of congenital muscular dystrophy (C.M.D.), as described in the literature, are reported. In two young sisters born from consanguineous parents the presenting signs were severe congenital hypotonia in one and hypotonia with arthrogryposis in the other. The two other cases were adult patients with a long standing disease, the onset haring been marked by a transient neonatal hypotonia in one and by a congenital torticollis in the other. All 4 patients had progressively increasing muscle retractions, with absent reflexes in three. C.P.K. was moderately increased in all patients. Electromyography demonstrated myopathic abnormalities in 3 cases, associated in 2 cases with misleading pseudo-neurogenic signs. MUscle biopsy showed non specific changes compatible with muscular dystrophy: fibrosis and/or fat involution was marked in all cases, while necrosis of fibers was rarely observed. Histoenzymology and morphometry confirmed the absence of lesion specificity and their results were variable from case to case. A review of 92 published cases demonstrated that the course of the disease is very variable. A fatal outcome occurs in 15% of cases, while the affection becomes worse or remains stable with about the same frequency. A progressive worsening of muscle retractions is a characteristic finding in C.M.D. Genetically, most cases are of recessive autosomic. The current nosology of C.M.D. is probably inadequate, the clinical picture including cases that are likely to be due to different mechanisms that 2 present methods of investigation cannot demonstrate.