Background: Advanced age is one of the factors that increase mortality in intensive care. Sepsis and multi-organ failure are likely to further increase mortality in elderly patients. We compared the characteristics and outcomes of septic elderly patients (> 65 years) with younger patients (≤ 65 years) and identified factors during the first 24 hours of presentation that could predict mortality in elderly patients. Methods: This study was conducted in a Level III intensive care unit with a case mix of medical and surgical patients excluding cardiac and neurosurgical patients. We performed a retrospective review of all septic patients admitted to our ICU between July 2004 and May 2007. In addition to demographics and co-morbidities, physiological and laboratory variables were analysed to identify early predictors of mortality in elderly patients with sepsis. Results: Of 175 patients admitted with sepsis, 108 were older than 65 years. Elderly patients differed from younger patients with regard to sex, temperature (37.2°C VS 37.8°C p < 0.01), heart rate, systolic blood pressure, pH, HCO3, potassium, urea, creatinine, APACHE III and SAPS II. The ICU and hospital mortality was significantly higher in elderly patients (10.6% Vs 23.14% (p = 0.04) and 19.4 Vs 35.1 (p = 0.02) respectively). Elderly patients who died in hospital had a significant difference in pH, HCO3, mean blood pressure, potassium, albumin, organs failed, lactate, APACHE III and SAPS II compared to the elderly patients who survived while the mean age and co-morbidities were comparable. Logistic regression analysis identified temperature (OR [per degree centigrade decrease] 0.51; 95% CI 0.306- 0.854; p = 0.010) and SAPS II (OR [per point increase]: 1.12; 95% CI 1.016-1.235; p = 0.02) during the first 24 hours of admission to independently predict increased hospital mortality in elderly patients. Conclusions: The mortality in elderly patients with sepsis is higher than the younger patients. Temperature (hypothermia) and SAPS II scores during the first 24 hours of presentation independently predict hospital mortality.