Seven episodes of rhabdomyolysis with acute renal failure (ARF) have been observed in 6 patients treated with various short-acting tranquilizers and antidepressants. Clinical features usually included severe hyperthermia, diffuse hypertonicity with or without coma, circulatory failure or unstable blood pressure, and often acute respiratory failure. Serum CPK were always elevated. The type of ARF was prerenal failure without oliguria in 5/7 episodes, and acute tubular necrosis in 2/7 episodes, requiring hemodialyses in one patient. Three patients died. In any case, the tranquilizers and antidepressants responsible for this syndrome were stopped, and electrolyte disorders and acidosis were corrected. Associated acute circulatory failure, septicemia and/or acute hepatic failure required prompt therapy, and artificial ventilation was required in 4 instances. The further use of phenothiazines, butyrophenones, sulpiride and their derivatives should be avoided in any patient having developed such an accident, whose pathophysiology is similar to that described in malignant hyperthermia of various origin.