We have observed six episodes of severe symptomatic hypoglycemia in 5 nondiabetic patients on chronic maintenance hemodialysis. The common factor in all 5 patients was propranolol administration for the treatment of hypertension. This observation suggests that β-adrenergic blockade may cause profound hypoglycemia in dialyzed patients with other predisposing factors such as poor nutrition, liver dysfunction or stress. On the basis of our experience, we recommend blood sugar determinations for propranolol-treated patients during dialysis against glucose-free dialysate