Background: obesity is associated with increased mortality and morbidity. The use of bariatric surgery has recently increased dramatically in order to lose weight fast; however, the heavy consequences and the long-term weight loss induced by bariatric surgery has favorable effects on life span remains unclear. Aim of Study: this study was aimed to explore knowledge and beliefs about safety, effectiveness and consequences of bariatric surgeries among community population in Jeddah city and to evaluate the role of demographic factors in shaping those beliefs, and assess possible associations between demographic characteristics with lose weight preventive behavior. Patients and methods: this study was done in 2016 and carried out among a sample of 474 citizens, of them 70.1% women and 29.9% men. The mean age of citizens was 35.77. To assess citizens' demographic factors, risk factors of obesity and beliefs about bariatric surgeries, consenting citizens responded to an anonymous online questionnaire. The data was entered and analyzed using SPSS version 20. Data were entered into the Statistical Package for Social Sciences (SPSS, version 20) and descriptive analysis conducted. Results: the results of the current study show that among the respondents, (24.5%) were obese, (13.7%) severely obese and (9.3%) were morbid obese. The majority of them believed that the lack of exercise is the cause of their obesity (45.7%), (71% ) of the respondents think that genetics play a role in obesity, (69.3%) of respondents have someone in their family who suffers from obesity and (61.6%) were not keen to exercise. The majority of respondents (77.4%) think that weight loss procedures contribute to weight loss, however (69.8%) are not of favor towards weight loss procedures to get rid of obesity, (63.4%) of them have not undergone any surgery, and (86.6%) of the respondents do not think of surgeries as their first choice to lose weight without exercise or diet, also (71.0%) think that weight loss procedures and its complications may lead to death.The majority of the respondents (74%) have inadequate beliefs about bariatric surgery and (50.8%) of the respondents have good knowledge on prevention behavior of obesity.