: Acute widespread peritonitis caused by a perforated hollow viscus is a potentially fatal illness. It's a common surgical emergency in many developing-country general surgical departments, and it's often associated with substantial morbidity and mortality. Grading the severity of acute peritonitis has greatly aided decision-making and improved the therapeutic success in the management of critically ill patients. Empirically based risk assessment for major clinical events has proven to be tremendously valuable in evaluating new medicines, monitoring resource utilisation, and improving care quality. A hospital based prospective observational study was conducted on patients operated on emergency basis for hollow viscus perforation admitted to the hospital, the study was conducted from OCT 2014 – SEP 2016 at Kamineni institute Medical sciences & hospital, Narketpally, Telengana. A series of 100 cases was compiled for this study during this period. The accuracy in outcome prediction of APACHE–II system was assessed by means of receiver operating characteristic curve and Pearson correlation coefficient. The Analytical data obtained was compared and discussed with the data available in the literature. A total of 100 patients were studied. Out of which there were 86(86%) survivors and 14(14%) non-survivors. Mean APACHE–II score of the study population was 9.80 with a range of 1-30. The predicted death rate for the study population was 16% and observed death rate was 14%. Mean APACHE–II score in survivors was 8.03 where as in non-survivors it was 20.64. The area under the curve using receiver operating characteristic curve analysis was found to be 0.985. The association between the APACHE-II score and the predicted death rate was flawless, with r = 0.99 and P0.001. In patients with peritonitis caused by hollow viscus perforation, an APACHE-II score of 11-20 was found to be a stronger predictor of mortality risk. In patient groups with APACHE-II scores of 0-10 and scores > 20, predicted death did not match observed mortality. APACHI-II scoring system can be used for assessment of group out come in patients with peritonitis due to hollow viscus perforation. However, it does not provide sufficient confidence for outcome prediction in individual patient.