Objective: The number of admissions to the emergency department (ED) of elderly patients who reside in nursing homes with a diagnosis of pneumonia continues to grow. This study was designed to assess factors that predicted mortality in the patient group defined as those with nursing home-acquired pneumonia (NHAP). Materials and Methods: This was a prospective, observational study conducted in a hospital ED. The data of nursing home patients admitted to the ED with a pneumonia presentation (NHAP) were compared with those of patients with communityacquired pneumonia (CAP). Factors that predicted mortality in the NHAP group were analyzed. SPSS for Windows, Version 16.0 software (SPSS Inc., Chicago, IL, USA) was used to perform the statistical analysis. Results: A total of 98 patients >18 years of age, 36 of whom were NHAP patients, were included in the research. The risk level and rates of intensive care admission and mortality were significantly higher in the NHAP group (p<0.05), and the thiol level, an antioxidant parameter, was lower in the NHAP group than that of the CAP group (p<0.001). Evaluation of the NHAP group alone revealed a higher mortality rate in patients with congestive heart failure, those hospitalized in intensive care, and those with high risk scores (p<0.05). The shock index (SI) value was found to be an independent predictor of mortality in the NHAP group. The study results indicated that each 0.1 unit increase in the SI increased mortality 3.637 times (95% confidence interval: 1.024-12.921) (p=0.046). Conclusion: The findings suggest that the SI could serve as a valuable marker for predicting mortality in NHAP patients.