Despite the effectiveness of bariatric surgery only 49% of the patients that enroll in bariatric surgery programmes complete the surgery. This study attempts to identify psychological barriers to bariatric surgery. A sample of 471 patients who were screened for medical indications for surgery, adequate health insurance and medical/psychological contraindications, were used. Participants were predominantly female (71.8%) and Caucasian (68.4%) with a mean body mass index (±standard deviation [SD]) of 47.84 (±7.53) and mean age (±SD) of 40.59 (±10.79). A total of 69.2% completed surgery (63.2% gastric bypass, 35.6% gastric band, 1.2% gastric sleeve). Participants with lower levels of global surgical anxiety, a preference for the gastric bypass, a childhood or adolescent onset of obesity, and more experience dieting, were more likely to complete surgery. No significant differences were found among groups for specific surgical anxieties or medical comorbidities. These findings suggest that factors that patients routinely report as surgical motivators, including comorbidities, may be necessary, but are not sufficient, for surgical completion. Other factors, such as a global surgical anxiety, and the patient's belief in their ability to lose weight without surgery, may play a large role in surgical attrition.