The purpose of this study was to conduct a systematic review and meta-analysis of the published literature to evaluate the diagnostic accuracy of fluorine-18 2-fluoro-2-deoxy-D-glucose (18F-FDG) PET or PET/computed tomography (CT) in the pretherapeutic staging of patients with small-cell lung cancer (SCLC). The authors conducted a systematic MEDLINE search of published articles. Two reviewers independently assessed the methodological quality of each study. We estimated the pooled sensitivity, specificity, positive and negative likelihood ratios (LR+ and LR−), and summary receiver operating characteristic curves in the detection of extensive disease (ED) in patients with SCLC. Twelve studies with a total of 369 patients met the inclusion criteria. The pooled estimates of sensitivity, specificity, LR+, and LR− of 18F-FDG PET or PET/CT for the detection of ED in SCLC were 97.5% [95% confidence interval (CI), 94.2–99.2%], 98.2% (95% CI, 94.9–99.6%), 19.86 (95% CI, 9.79–40.30), and 0.06 (95% CI, 0.03–0.10), respectively. Whole-body 18F-FDG PET or PET/CT is a valuable imaging tool for the pretherapeutic assessment of ED in patients with SCLC.