Background: APACHE IV and SAPS II are ICU scoring systems used to predict mortality in critically ill patients in the ICU. Aim: To compare mortality prediction using APACHE IV and SAPS II in an Indian ICU. Methods: This prospective study included 225 patients. SAPS II and APACHE IV scoring and predicted mortality were obtained for each patient using online calculators and correlated with actual mortality and length of stay. Results: 183/225 of these admissions were due to medical causes. The mean±SD SAPS II score was 37.97 (±15.85) and APACHE IV score was 64.15 (±20.04). The median SAPS II predicted mortality rate was 19.6% and by APACHE IV was 17.4%. Actual mortality was 25.33%. Area under the curve (AUC) for SAPS II was 0.723 and APACHE IV was 0.701. AUC for SAPS II and APACHE IV for medical admissions were 0.712 and 0.681 respectively and for surgical admissions was 0.803 and 0.811 respectively. The best cut off value of SAPS II was 37 and APACHE IV was 70.5 for surgical patients. The mean predicted mortalities for patients with SAPS II score <37 and .37 were 4.95±3.87% and 37.15±16.5% respectively and APACHE IV score <70.5 and .70.5 were 16.82±11.48% and 40.6±15.72% respectively. There was no correlation between predicted and actual length of stay. Conclusions: Both APACHE IV and SAPS II ICU scoring systems are inaccurate in predicting overall mortality in our ICU. APACHE IV is not reliable in predicting length of stay of all patients in our ICU.