Obesity is a worldwide epidemic that threats the health and body image of those who suffer from this condition. While bariatric surgery has been shown to effectively assist patients to achieve weight loss goals and to improve body image, related research on this intervention is lacking in Taiwan. The purpose of this research is to investigate the effect of bariatric surgery on body image in obese patients. This study used a longitudinal design. Data was collected from 2 hospitals located in northern and southern Taiwan. A total of 56 obese patients who had undergone bariatric surgery enrolled as participants, and the completion rate was 93.3%. Participants responded to a validated body image questionnaire immediately prior to and 3 months after bariatric surgery, with data used to assess the effects of the surgery. SPSS 20.0 software for windows was used for data analysis. Participant scores for body image were low on the questionnaire administered prior to surgery, with a significant negative correlation identified between body mass index (BMI) and the value of appearance (r = -.36, p < .01). After bariatric surgery, the average EWL was 42.08%, which effectively achieved expected weight loss goals. Variables including overall body image, appearance evaluation, orientation, and body satisfaction of participants were significantly improved. Only the variable of muscle tension did not improve significantly. Postoperative body image did not correlate with either BMI or EWL. Three months after the bariatric surgery, the body image, appearance evaluation, and physical appearance satisfaction of participants had significantly improved. However, there was no improvement in muscle tension scores. In order to improve the post-surgery body image of patients, we recommend that healthcare workers provide patients with proper expectations of bariatric surgery and teach patients appropriate muscle-tension exercises. This paper reports the relation between bariatric surgery and body image. The results provide evidence for clinical and future research in this field.