This study aimed to investigate the effects of postoperative administration of 7.5% hypertonic saline (HTS) on fluid balance and surgical outcome after open resection of colorectal carcinoma. The study included 30 patients randomly allocated into 2 equal groups: HTS group and control group (CG) according to postoperative fluid therapy regimen. Patients in CG were continuously transfused with Ringer lactate (RL) solution and in HTS group patients received 4 ml of 7.5% HTS/kg body weight once at time of transport to the ICU and once on the 1st POD and were continuously transfused with RL solution so as to keep stable hemodynamics and enough urine outputs. The fluid volumes transfused and discharged (urine & drains) were recorded and fluid balance (=input-output) was calculated. Serum sodium concentration was checked every 6 h; postoperative complications and duration of postoperative hospital stay were reported. Postoperative HTS fluid therapy significantly (p