BACKGROUND: Intragastric balloons (BIB) are routinely used for weight reduction. They should be placed to the gastric fundus, as this place is believed more effective for achievement of satiety and thus weight reduction. The aim of the present study was to evaluate whether the balloon position may affect 6-month weight loss as well as first-month side-effects, i.e. nausea, vomiting, and gastroesophageal reflux.METHODS: From a total of 158 BIB-treated obese individuals, 105 females were found eligible, since the balloon in the stomach was found upon removal in the same position (fundus or antrum) placed at the time of insertion. These subjects were divided into fundus and antral groups. Data related to obesity were recorded on day 0 and upon BIB removal, 6 months thereafter. Data related to transient side-effects (nausea, vomiting, gastroesophageal reflux) were recorded on days 0-3, 7, and weekly thereafter, for 1 month.RESULTS: BIB placed in the antrum was found to have significantly better results on weight loss parameters, while nausea, vomiting (p = 0.02) as well as gastroesophageal reflux still remained up to the fourth week in a relation to the fundus group. Similarly, the rate of gastric distension was found significantly increased (p = 0.001) during the days 1-3 in fundus group in relation to antrum, followed by a progressive decrease in both groups.CONCLUSIONS: Intragastric balloon placed in the antrum lead to better results in weight reduction but to longer duration of tolerability-related side-effects, i.e., nausea, vomiting, and gastroesophageal reflux.