Background: Healthcare-associated infections are costly and increasingly viewed as a quality indicator of care. Although strategies to reduce infections have become widespread, few studies have formally investigated the role of undernutrition on the development of infection related complications in children after surgery. Aim: To determine from systematic review of the literature whether undernutrition is prognostic of postoperative infection complications in children. Methods: Electronic bibliographic and research databases were searched from 1950 to 2014. Inclusion criteria were studies in children (<18 years) evaluating preoperative nutritional status and reporting postoperative infection complications. Quality assessment was performed using the Newcastle-Ottawa Scale with appraisal and data extraction performed independently by two reviewers. Disagreements were resolved by a third reviewer. Findings: Ten cohort and two case-control studies met the inclusion criteria and used a variety of nutritional assessments. Postoperative infection complications were either reported combined or individually. Quality of the evidence was judged low in the majority of studies, with only two of moderate quality. Direct comparison between studies was difficult due to clinical and diagnostic heterogeneity. Univariate statistical analysis was suggestive of a relationship between undernutrition and postoperative infection complications. Conclusion: There was low quality evidence that undernutrition may be predictive of postoperative infection complications in children. However, inconsistencies in nutritional and outcome assessments made drawing conclusions difficult. Larger studies are warranted to investigate further this potential prognostic relationship.