Purpose: This study aimed to determine the C-reactive protein (CRP) ratio for the survival of patients with Fournier gangrene (FG). Methods: Fifty-two patients with FG between January 2011 and September 2018 were retrospectively analyzed. Data on clinical presentation, Fournier Gangrene Severity Index (FGSI), CRP ratio, management, and outcome were analyzed. The CRP ratio was calculated as preoperative CRP/postoperative CRP value that measured 48 hours after surgical intervention. Possible alternative cutoff points for the FGSI and CRP were determined by receiver operating characteristic (ROC) analyses. The risk factors related to the prognosis were evaluated by univariate and multivariable logistic regression analyses. Results: The mean CRP ratios were 6.7±6.6 in the survivor group and 1.2±0.8 in the nonsurvivor group (P=0.001). FGSI was significantly higher in the non-survivor group compared to survivor group (8.5±2.5 vs. 3.5±2.2, P=0.001). There was a negative correlation between FGSI and CRP ratio (r=–0.51). ROC analysis determined the cutoff value as 1.78 for CRP (sensitivity, 86%; specificity, 82%; area under the ROC curve, 0.90) to predict death. The incidence of death for patients with CRP ratio of ≤1.78 increased 26.7 fold for those with CRP ratio of >1.78 (95% confidence interval [CI], 4.8–146.5; P=0.001). In the multivariable logistic regression model, CRP ratio (odds ratio [OR], 10.3; 95% CI, 1.5–72.2; P=0.019) and FGSI (OR, 17.8; 95% CI, 2.6–121.1; P=0.003) were independent risk factors for death. Conclusion The CRP ratio is a simple method to use to predict mortality in FG.