The Pediatric Early Warning System (PEWS) score may be useful for detection of deterioration in clinical condition. In this retrospective study, the cases were patients transferred to the pediatric intensive care unit (PICU), and controls were those not transferred to the PICU. The maximum PEWS score in both groups were analyzed using Mann-Whitney U test and receiver operating characteristic curve (ROC). The study population included 100 cases and 250 controls. There was no difference in the age of cases and controls (6.3 vs 6.3 years). The length of hospital stay (18.09 ± 32 vs 3.93 ± 2.9 days; P < .001) and the maximum PEWS score (2.95 ± 1.5 vs 1.4 ± 0.8) were significantly higher for the cases (P < .0001). The PEWS score area under the ROC was 0.81 (95% confidence interval = 0.75-0.86). The sensitivity and specificity for a score 2.5 were 62% and 89%, respectively. The use of the modified PEWS score can help identify patients on wards who are at risk for deterioration.