OBJECTIVE: This study aimed to develop and test a novel mindfulness-based intervention (MBI) designed to control weight after bariatric surgery. DESIGN: Randomized, controlled pilot trial. SETTING: Beth Israel Deaconess Medical Center, Boston, MA, USA. INTERVENTIONS: Bariatric patients 1-5 years post-surgery (n=18) were randomized to receive a 10-week MBI or a standard intervention. MAIN OUTCOME MEASURES: Primary outcomes were feasibility and acceptability of the MBI. Secondary outcomes included changes in weight, eating behaviors, psychosocial outcomes, and metabolic and inflammatory biomarkers. Qualitative exit interviews were conducted post-intervention. Major themes were coded and extracted. RESULTS: Attendance was excellent (6 of 9 patients attended ≥7 of 10 classes). Patients reported high satisfaction and overall benefit of the MBI. The intervention was effective in reducing emotional eating at 6 months (-4.9±13.7 in mindfulness vs. 6.2±28.4 in standard, p for between-group difference=0.03) but not weight. We also observed a significant increase in HbA1C (0.34±0.38 vs. -0.06±0.31, p=0.03). Objective measures suggested trends of an increase in perceived stress and symptoms of depression, although patients reported reduced stress reactivity, improved eating behaviors, and a desire for continued mindfulness-based support in qualitative interviews. CONCLUSIONS: This novel mindfulness-based approach is highly acceptable to bariatric patients post-surgery and may be effective for reducing emotional eating, although it did not improve weight or glycemic control in the short term. Longer-term studies of mindfulness-based approaches may be warranted in this population. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT02603601.