Introduction: The intragastric balloon is a minimally invasive technique used to treat obesity by reducing hunger and inducing satiety as a result of gastric volume restriction, thus it could be ideal to treat young people who are thought to be easier to change their eating behavior. Aim: The purpose of this prospective clinical study was to investigate the effectiveness of intragastric balloon on obese adolescents, after a six-month period of treatment. Material: Fourteen adolescents -aged 18,5±2,5 yrs- treated by intragastric balloon were studied prospectively. Mean baseline Body Mass Index [BMI] was 39,8 ± 5,8kg/m2 and %Fatty Mass [FM] 41,7 ± 5,4. The data collected every month for the 6mo period was: Body Weight [BW], BMI, Resting metabolic Rate [RMR] by indirect calorimetry, %FM, %Excessive Weight Loss [%EWL] and %Actual Caloric Intake [%ACI]. Appetite related sensations scores [hunger, satiety, desire for food] were also assessed monthly by visual analogue scales [VAS]. The number of follow-up visits was considered as a marker of compliance. Results: Median baseline values were as follows: BM 118kg [range 80 to 174], BMI 39,1kg/m2 [range 33 to 54] [>95th percentile],%FM 42 [range 33 to 49] and %ACI 116,6 [range 60 to 200,5]. After a 6mo period, just before the removal of the balloon, all measured parameters exhibited a statistically significant reduction: the median BW was found to be 108kg [range 62 to 162, p=0,002], the BMI 37kg/m2 [range 26 to 50, p=0,001], %FM 40 [range 20 to 49, p=0,009], the %EWL was 14,29 [range 3,33 to 69,23, p=0,021] and the %ACI=86 [range 33 to 153,96, p=0,02]. Appetite related sensation score was unchanged.The median number of follow-up visits was 4 [range 2 to 7]. Conclusions: Although the number of follow-up visits during the 6 month treatment generally reveals poor compliance,a small though significant weight loss, as a consequence of reduction in the energy intake is prominent. Based on the above findings, a better pre-procedure screening for the appropriate candidates for treatment as well as a better scheduled approach by a multi-disciplinary group, including a dietician and a psychologist is considered mandatory.