[en] Pseudo-Bartter syndrome presents the same clinical and biological characteristics as Bartter syndrome but without primary renal tubule abnormalities. We relate the case of a premature baby presenting at birth with severe hypokalemic metabolic alkalosis associated with hyponatremia and hypochloremia. Maternal blood at the time of delivery showed the same electrolyte perturbations. The baby's mother had suffered from anorexia and vomiting during pregnancy. A few weeks after birth the baby's blood abnormalities had almost returned to normal. Chloride depletion is at the origin of both maternal and fetal hypokalemic alkalosis.