Background: Pediatric intensive care units (PICU) have special equipment for treatment of children with life-threatening conditions Platelet-lymphocyte ratio (PLR) is a novel inflammatory marker. It has been shown that PLR can be used as a useful marker for early diagnosis and treatment of some diseases. This study aimed to research whether PLR is a predictive factor of mortality risk in PICU patients. Methods: This retrospective and prospective observational cohort study was conducted on 100 children hospitalized in the PICU in Benha University Hospitals. Patients were evaluated by different disease severity scores using sequential organ failure assessment (SOFA), pediatric index of mortality 2 score (PIM2), preserved ratio impaired spirometry (PRISM III) and pediatric logistic organ dysfunction (PELOD). Results: PLR, and NLR were significantly lower in non- survivors compared to survivors (P