Background: Endoscopic ablation of Barrett's esophagus (BE) is a treatment option for patients with high-grade dysplasia (HGD) and intramucosal carcinoma (IMCA). Objective: To assess the safety and efficacy of a unique noncontact method of liquid nitrogen cryoablation as measured by histologic response rate and cancer-free survival. Design: Single-center, nonrandomized cohort study. Setting: Referral center, conducted between September 2005 and September 2008. Patients: Patients with BE and HGD or IMCA who were deemed inoperable or who refused esophagectomy Age, length of BE, and previous ablation were not exclusion criteria. Intervention: Cryoablation every 6 weeks until endoscopic resolution. EMR was used for pathologic staging of nodular areas before cryoablation and focal residual areas during the follow-up period. Main Outcome Measurements: Histologic response was defined by the worst pathology obtained at any level of the esophagus or gastric cardia in 1 of 3 categories: (1) incremental = absence of HGD and IMCA in all biopsy specimens, (2) partial = residual IMCA with absence of any dysplasia, and (3) complete = absence of any intestinal metaplasia or dysplasia. Results: Thirty patients underwent ablation; 9 had undergone previous ablation or mucosectomy. Twenty-seven of 30 patients (90%) had downgrading of pathology stage after treatment. Elimination of cancer or downgrading of HGD at last follow-up was 68% for HGD and 80.0% for IMCA, with a median follow-up period of 12 months (25th percentile, 6; 75th percentile, 24). Minor adverse events included mild pain (n = 7), a low incidence of mild strictures (n = 3), and lip ulcer (n = 1). One major adverse event (perforation) in a patient with Marfan syndrome occurred with the prototype system. During follow-up, 3 of 6 patients with complete response had recurrence of dysplasia or cancer in the gastric cardia. Limitation: A nonrandomized, single-center study with a heterogeneous cohort of patients. Conclusions: Patients with BE and HGD or IMCA have a positive response to endoscopic cryotherapy at 1-year follow-up. (Gatrointest Endosc 2009;70:635-44.)