Renal hemodynamics, electrolyte excretion and plasma level of glucorticoids were studied in pregnant sheep before and after the experimental induction of toxemia. Marked renal ischemia occurred in the animals which developed toxemia. This abnormality occurred concomitantly with an increase in plasma corticoids. Despite the renal ischemia, arterial pressure remained the same. There are some similarities between the toxemia of the sheep and that of human pregnancy.