Acute coronary syndrome (ACS) is an urgent clinical condition of cardiovascular diseases. The present study evaluated the predictive efficacy of the hemoglobin to serum creatinine ratio (Hgb/Cr) on long-term mortality in patients with ACS. The ratio, representing the proportion of the 2 values, is cheap, practical, and very easy to calculate at the bedside. Our study included 475 patients who were admitted to the coronary intensive care unit with a diagnosis of ACS and who underwent coronary angiography. The Hgb/Cr ratio was calculated by dividing the admission hemoglobin by the admission serum creatinine. All patient data were collected from the electronic hospital information system, patient files, and the hospital's archive. A comparison of the patients laboratory findings revealed that the Hgb/Cr ratios differed significantly between the survivor and non-survivor group [16.6 (7.7-49) vs 13.8 (4.91-32.8), respectively; P < .001]. A univariate Cox regression analysis showed that the Hgb/Cr ratio was statistically significant in predicting long-term mortality (0.836; 95% confidence interval [CI]: 0.781-0.895; P < .001). After adjusting the model by adding clinically and statistically significant variables, the Hgb/Cr ratio was still an independent predictor of long-term mortality (0.886; 95% CI: 0.815-0.963; P = .004). The Hgb/Cr ratio's discriminant ability was tested with an receiver operating characteristic curve analysis. The Hgb/Cr ratio's area under the curve value was 0.679 (95% CI: 0.609-0.750; P < .001). A survival analysis using the Kaplan-Meier curve of the 2 Hgb/Cr ratio groups (according to cutoff value) revealed that the low-Hgb/Cr group had a significantly higher mortality rate than high-Hgb/Cr group. The Hgb/Cr ratio was found to be an independent predictor of long-term mortality in ACS patients.