Introduction The impact of esophageal tumor length on pT1 esophageal adenocarcinoma has not been well evaluated. Methods Case histories of all patients (n = 133) undergoing esophageal resection from 1979 to 2007 with pT1 adenocarcinoma of the esophagus were reviewed. Univariate and multivariate analyses of esophageal tumor length and other standard prognostic factors were performed. Results Patients with early-stage pT1 esophageal adenocarcinoma with tumors less than 3 cm demonstrate decreased long-term survival (3 years: >3 cm = 46% vs 93%; P < .001) and higher risk of lymph node involvement (lymph node positive: >3 cm = 47% vs 10%; P < .001). Multivariable analysis shows that esophageal tumor length (>3 cm) is an independent risk factor for survival in patients with pT1 early-stage esophageal cancer (hazard ratio: 4.8, 95% confidence intervals: 1.4–16.5; P < .001) even when controlled for submucosal involvement, lymph node involvement, and lymphatic/vascular invasion status. In combination with submucosal involvement, esophageal tumor length (>3 cm) identifies a high-risk population of pT1 esophageal adenocarcinoma (3 years: group 1 0 risk factors = 100%, group 2 1 risk factor = 87%, and group 3 2 risk factors = 33%; P < .001). Conclusions This study demonstrates that esophageal tumor length (>3 cm) is a risk factor for long-term survival and lymph node involvement in early-stage pT1 esophageal adenocarcinoma. Esophageal tumor length (>3 cm) in combination with submucosal involvement may help to identify a high-risk group of patients with pT1 esophageal adenocarcinoma.