Objective To evaluate the threshold for platelet transfusion in children admitted to a pediatric intensive care unit (PICU). This is a retrospective chart review study, conducted at our tertiary level PICU and is related to critically ill pediatric patients who required platelet transfusion. Methods We retrieved the target patient population data from our blood bank database. The patients were subdivided into four subgroups: hematologic (hematologic malignancies, bone marrow suppression, hemolytic anemia, and sickle cell disease), surgical (post-surgical, trauma and acute bleeding), the unstable fraction of inspired oxygen (FiO2 > 0.6 and/or inotropic support), and the stable patients. Critically ill children between one month and 21 years of age were enrolled. We excluded patients who underwent extracorporeal membrane oxygenation (ECMO). Results A total of 197 transfusion episodes in 64 patients were analyzed. The distribution of transfusions episodes included hematologic 82% (n=161), surgical 7% (n=13), unstable 8% (n=16), stable 3% (n=7). The mean standard deviation (SD) of pre-transfusion platelet count (x1000) in all the patients and children in hematologic, surgical, unstable and stable groups were 29 (22), 29 (19), 47 (46), 28 (19), and 24 (14), respectively. The platelet count threshold for transfusion among the surgical group was higher compared to hematologic and unstable groups (p <0.001; analysis of variance (ANOVA) with multiple comparison tests). The mean platelet count during all episodes increased from 29 (22) to 71 (57) (p <0.05; paired t-test). The post-transfusion increase in platelet count was significantly higher among surgical and unstable patients compared to hematologic patients (p <0.001; ANOVA with multiple comparison tests). Conclusion The most common indication for platelet transfusion in the pediatric intensive care unit (PICU) is the underlying hematologic condition. The platelet count threshold for transfusion varied with the clinical condition and is higher among the surgical patients. The rise of platelet count after transfusion was higher among the surgical and unstable patients.