Objective To investigate the relationship between pretreatment plasma D-dimer levels and survival in Chinese patients with small cell lung cancer (SCLC). Methods This retrospective study enrolled 82 patients with SCLC treated at Beijing Chaoyang Hospital, Capital Medical University, from January 2012 to January 2015. All patients were followed up. Associations between pretreatment plasma D-dimer levels measured by immunoturbidimetric assay and clinical outcomes were analyzed by Kaplan–Meier and multivariate analyses, using a cut-off level of 0.55 mg/L fibrinogen equivalent units (FEU). Results Median progression-free survival (PFS) and overall survival (OS) were significantly higher in patients with low D-dimer levels (≤0.55 mg/L FEU; 8.0 and 17.0 months, respectively) compared with patients with high levels (>0.55 mg/L FEU; 5.0 and 9.0 months, respectively). Plasma D-dimer levels, Karnofsky performance status, N stage, TNM stage, treatment, and neuron-specific enolase (NSE) levels were significantly associated with PFS, while D-dimer levels, N stage, TNM stage, and treatment were significantly associated with OS. Multivariate analysis revealed that TNM stage, treatment, and NSE levels were independently associated with PFS, while D-dimer levels and treatment were independently associated with OS. Conclusions Pretreatment plasma D-dimer levels were independently associated with OS in patients with SCLC.