Prophylactic administration of Rh immunoglobulin to all Rh-negative women undergoing sterilization procedures has been advocated to prevent Rh isoimmunization, thus allowing transfusion of Rh-positive blood to those individuals in the future. However, results from a survey of 23 hospitals in the United Stales and 95 hospitals in the stale of Iowa indicate that Rh-positive blood is rarely given to Rh-negative women even in an emergency. Since only 7 of 100 Rh-negative women are sensitized by their last pregnancy and the chance that any of those 7 women will ever receive Rh-positive blood is probably less than 2%, the advisability of routinely using Rh immunoglobulin in this situation is questioned.