BACKGROUND The concept of Paediatric intensive management is changing rapidly worldwide. But there are no definite parameters available for the assessment of the patient's severity. There was an intense need to conduct study which deals with the assessment of patient but also helps in prognosticating the patient and help in counseling the parents at the time of admission. The severity of sickness is assessed on the basis of PRISM-III Score (Paediatric Risk of Mortality), that is an internationally accepted standard score. MATERIALS AND METHODS The present prospective observational study was carried out during October 2015 to September 2016 in Paediatric Intensive Care Unit (PICU) of Prakash Institute of Medical Sciences and Research, Urun-Islampur. All patients admitted to PICU during October 2015 to September 2016 who fulfilled the inclusion criteria were enrolled in the study. RESULTS Among the physiological parameters BP, GCS and pupils showed statistically significant association with mortality. Heart rate and temperature did not show any significant relation with mortality. Only 4 patients had severe tachycardia as risk factor. We did not find any significant association between these parameters and mortality. Among lab parameters studied, ABG showed significant association with mortality with 64.7% mortality for children with pH less than 7.28. On evaluation of chemistry tests Potassi um, Creatinine and BUN showed good association with mortality. 38.5% mortality for glucose values < 80, which was statistically significant. Based on Haematological tests, PT and PTT showed significant association with mortality. WBC count and platelet count did not show significant association with mortality. CONCLUSION PRISM III score has good predictive value in assessing the probability of mortality.