Malnutrition is well recognized as a potential cause of increased morbidity and mortality in surgical patients. Early postoperative enteral nutrition through a feeding jejunostomy has been shown to improve results in patients undergoing major resections for gastrointestinal malignancies, trauma, and perforation peritonitis. We conducted a prospective study to assess the feasibility and short-term efficacy of early enteral feeding through a nasoenteric tube placed intraoperatively in patients with nontraumatic perforation peritonitis with malnutrition. One hundred patients with nontraumatic perforation peritonitis with malnutrition undergoing exploratory laparotomy were randomly divided into a test group (TG) and a control group (CG) of 50 patients each. TG patients had a nasoenteric tube placed at the time of surgery and were started on an enteral feeding regime 24 hours postoperatively. Patients in CG were allowed to eat orally once they passed flatus. The differences between the two groups with respect to nutritional intake in terms of energy and protein, changes in nutritional status as assessed by anthropometric, biochemical, and hematological values, amount of nasogastric aspirate, return of bowel motility, and complication rates were analyzed. The nasoenteric feeding was well tolerated. Total calorie and protein intake in TG was significantly higher than in CG: 981 vs. 505 kcal (p < 0.01), protein 24 vs. 0 g on day 3 and 1498 vs. 846 kcal (p < 0.01), protein 44 vs. 23 g (p < 0.01) on day 7, respectively. There was reduction in the amount of nasogastric aspirate in TG compared with that in CG: 431 vs. 545 ml/24 h on day 2 and 301 vs. 440 ml/24 h on day 3, respectively. There was much faster recovery of bowel motility in TG than in CG at 3.34 vs. 4.4 days (p < 0.01). Complications developed in 39 of 50 patients in TG and in 47 of 50 in CG. The major complications occurred in 6 patients in TG and 12 patients in CG (p < 0.05). Patients with perforation peritonitis with malnutrition are likely to develop large energy deficits postoperatively, resulting in higher incidence of infective complications. Early enteral feeding through a nasoenteric tube is well tolerated by these patients and helps to improve energy and protein intake, reduces the amount of nasogastric aspirate, reduces the duration of postoperative ileus, and reduces the risk of serious complications.