A retrospective study was undertaken over an eight-year period to assess the mortality rate of 66 newborns who had undergone surgery in our clinic because of peritonitis. The mortality rate for the patients admitted in poor condition was 95.2 percent, whereas it was 45.5 percent for those in good condition. There was a 100 percent mortality associated with newborns that had hypothermia and with those that had severe respiratory difficulties, whereas it was 92.3 percent for low-birth-weight infants and 86.5 percent for dehydrated infants. All babies with sclerema neonatorum died. The newborns with white blood cell counts under 5,000/mm3 also did not survive (83.3%). Etiologically, congenital megacolon, meconium ileus and spontaneous gastrointestinal perforations were the most frequent anomalies leading to death (100%). In the newborns with gastrointestinal perforations, most deaths occurred in patients with perforations of the cecum, duodenum and stomach (100%). Mortality seemed to be greater in patients with complications (77.3%), and it rose to 83.3 percent for patients who had to undergo a repeat operation due to complications. The overall mortality rate was found to be 71.2 percent.