BACKGROUND & AIMS: Although patients with Barrett’s esophagus commonly undergo endoscopic surveillance, its effectiveness in reducing mortality from esophageal/gastroesophageal junction adenocarcinomas has not been evaluated rigorously. METHODS: We performed a case-control study in a community-based setting. Among 8272 members with Barrett’s esophagus, we identified 351 esophageal adenocarcinoma: 70 in persons who had a prior diagnosis of Barrett’s esophagus (who were eligible for surveillance); 51 of these patients died, 38 as a result of the cancers (cases). Surveillance histories were contrasted with a sample of 101 living persons with Barrett’s esophagus (controls), matched for age, sex, and duration of follow-up evaluation. RESULTS: Surveillance within 3 years was not associated with a decreased risk of death from esophageal adenocarcinoma (adjusted odds ratio, 0.99; 95% confidence interval, 0.36-2.75). Fatal cases were nearly as likely to have received surveillance (55.3%) as were controls (60.4%). A Barrett’s esophagus length longer than 3 cm and prior dysplasia each were associated with subsequent mortality, but adjustment for these did not change the main findings. Although all patients should be included in evaluations of effectiveness, excluding deaths related to cancer treatment and patients who failed to complete treatment, changed the magnitude, but not the significance, of the association (odds ratio, 0.46; 95% confidence interval, 0.13-1.64). CONCLUSIONS: Endoscopic surveillance of patients with Barrett’s esophagus was not associated with a substantially decreased risk of death from esophageal adenocarcinoma. The results do not exclude a small to moderate benefit. However, if such a benefit exists, our findings indicate that it is substantially smaller than currently estimated. The effectiveness of surveillance was influenced partially by the acceptability of existing treatments and the occurrence of treatment-associated mortality.