This study examined the role of pretreatment albumin-to-fibrinogen ratio (AFR) in the prognosis of small-cell lung cancer (SCLC) patients receiving first-line platinum-based chemotherapy. A total of 131 SCLC patients were enrolled. The predictive value of the AFR for progression free survival (PFS) and overall survival (OS) were evaluated by receiver operating characteristic (ROC) curve analysis. The predictive factor of survival was assessed by univariate and multivariate Cox proportional regression analysis. The correlation between OS, PFS and AFR was determined by the log-rank test using the Kaplan-Meier method. AFR was an effective predictor of OS in SCLC patients with a cut-off value of 7.78. AFR was independent risk factors for OS and PFS. Kaplan Meier analysis showed that PFS and OS in patients with high AFR levels were significantly higher than those with low AFR levels. These results suggest that AFR could be an effective predictor of survival in patients with SCLC.