The goal of this study was to evaluate the safety and the impact on weight loss of a new swallowable gastric balloon. In this prospective pilot study, 17 overweight or obese patients were included. Up to three balloons were ingested under fluoroscopic control. All balloons were removed by upper GI endoscopy, 12 weeks after the ingestion of the first balloon. 43 out of 44 attempts (98 %) to swallow a balloon were successful. Nausea and stomach pain were the most frequent side effects. Endoscopic procedures for balloon removal were uneventful. Weight loss was significant at weeks 4, 8, and 12. This pilot study showed no significant side effects induced by up to three balloons, and a significant weight loss.