Fifteen patients were given parenteral nutrition with hyperosmolar glucose during the postoperative period (days 1 to 5): nine received an average of 10.5 gm of nitrogen and 2,340 kilocalories/day, six were given an average of 5.9 gm of nitrogen and 1,600 kilocalories/day. Eight patients (controls) received no nitrogen and 520 kilocalories/day. The results of this study confirm our early findings that total parenteral nutrition is capable of reversing the negative nitrogen balance of the immediate postoperative period; this reversal depends on administration of adequate nitrogen and calories. In patients with moderate surgical procedures, at least 8 gm of nitrogen and 1,800 kilocalories/day are required to correct the negative nitrogen balance. When total parenteral nutrition is instituted, adequate nitrogen and calories should be given, even if insulin is required to control hyperglycemia.