The purpose of this study is to detect the predictive power of the modified early warning score with rapid lactate level (ViEWS-L) on mortality in critical patients over the age of 65 years admitted to the emergency department (ED). A total of 616 non-traumatic patients admitted to the Uludag University Faculty of Medicine ED who were 65 years of age or older were included in this study (Ethics board number: 2015-4/8). In this prospective study; the ViEWS-L score of the patients were calculated. The results have been evaluated with rate of mortality in the first 24 h starting from submission. The area under the ROC curve was found 0.872 and the cut-off value to detect mortality was found 10.83 for the ViEWS-L score. In the model obtained by the univariate binary logistic regression analysis, ViEWS-L score was found statistically significant and it was determined that mortality risk increased 1.286 times for each unit increase in the score of ViEWS-L score. As a result of this research, it was found that ViEWS-L scoring system is effective in determining the mortality of 65 years and older patients.