Previous nuclear disease was found twice: Mc Ardle disease, dermatomyositis. Causative factors were: strenous exercise, hyperthermia, intoxication, influenza. Myalgias and/or myoedema was recorded in ten cases, associated with an hypovolemia of variable severity in eight. Oligo-anuria was observed in eight cases. The acute renal failure (ARF) was characterized by an increase in the serum creatinin more important than the rise in the blood urea and, in some cases, severe metabolic disturbances: hyperkaliema (6 cases), hypocalcemia (5 cases), hyperphosphatemia (5 cases) and hyperuricemia (5 cases). Diagnosis was made by the increase in sera of the muscles enzymes, specially the CPK and the search for myoglobinuria, positive during the first seven days. A complete recovery of renal function was observed in the nine survivors with a transient and moderate hypercalcemia in three. Three patients had persistant neuro-muscular deficiencies. Non traumatic rhabdomyolysis is not a rare cause of ARF and should be considered when the etiology of ARF is uncertain.