Introduction: Appendicitis can be classified as non-perforated and perforated; based on such classification, the reported organ-space surgical site infection (OS-SSI) rate is 0.8% and 18%, respectively.Objective: To establish the prevalence of OS-SSI in patients with perforated appendicitis treated in a pediatric hospital in 2012.Materials and methods: Retrospective, observational and descriptive study conducted at Fundación Hospital Pediátrico La Misericordia, with a random sample of 200 patients, of which 160 met the inclusion criteria.Results: 20 patients (12.5%) presented with OS-SSI and all of them received antibiotic treatment; 70% did not require abscess drainage. Patients ≥8 years of age had 5 times more abscesses than younger ones (17.6% vs. 3.4%). OS-SSI was found in 33% of patients with free fecalith and in 50% of the patients who required postoperative management at the ICU vs. 9.5% of the patients who received management in the intermediate care unit and the inpatient hospital floors. The total rate of surgical site infection was 24.3% (11.8% superficial, 0% deep and 12.5% organ-space).Conclusions: The prevalence of OS-SSI found here is lower than what has been reported in the literature. Being 8 years or older and having free fecalith are risk factors to develop this type of infection. The higher frequency of OS-SSI in patients treated at the ICU during the post-operative period observed here suggests that this condition may be associated with septic shock.