BACKGROUND: Surgical treatment of obesity does not lead to equal results in every patient. In addition to surgical techniques, a number of pyschological factors (depression, self-esteem, body dissatisfaction, interpersonal relationship problem) are known to influence the results. The aim of this study was to compare the psychological characteristics between obese people who underwent surgical treatment, obese subjects without surgery, and normal weight subjects. The psychological characteristics were then evaluated for any association among them. METHODS: The study included a total of 90 obese patients, including 30 patients who underwent surgical treatment for obesity, 30 obese patients who did not undergo surgical treatment, and 30 normal weight participants who received no treatment. Participations were all assessed for body shape dissatisfaction, depression, interpersonal relationship issues and self-esteem through a self reported questionnaire. RESULTS: Subjects from the surgical group scored the highest in body shape dissatisfaction, whereas subjects of non surgical obese group showed highest rate of depression and lowest self esteem compared to the other groups. As for interpersonal relationship issues, no significant difference was noted among the different groups. In the surgical group, a full mediating effects of self-esteem was found between body shape dissatisfaction and depression. CONCLUSION: This study shows that assessing patient's psychological state and providing proper intervention for body dissatisfaction, depression or low self esteem prior to surgical treatment for obesity seem necessary and important for obesity treatment overall.