Objective: To identify poor prognostic factors in the surgical approach for peritonitis secondary to neonatal intestinal perforation at the National Hospital of Pediatrics. Methods: Oinical trial cross sectional study analysing the relationship among poor prognostic factors in the surgical approach for peritonitis secondary to neonatal intestinal perforation. Results: Poor prognostic factors resulting in high mortality rate in surgical patients for peritonitis secondary to neonatal intestinal perforation are: preoperative respiratory failure, acid-base imbalance, sepsis, pre-operative shock and birthweight of less than 1500g. Conclusion: Poor prognostic factors are primarily pre-operative: respiratory failure, acid-base imbalance, sepsis and shock. Pre-operative intensive care and management for respiratory failure, shock, add-base imbalance and good antibiotic treatment in case of sepsis are required to reduce the postoperative mortality rate.