Objective Bariatric surgery is not a risk-free procedure and requires lifelong patient compliance in the postoperative period. Although the risks involved in bariatric surgery and the importance of lifelong follow-ups in the postoperative period are explained to patients in detail through verbal and written informed consent, the strong desire for weight loss can sometimes cause patients and their families to be ignorant of the mentioned issues preoperatively. The objective of this study is to evaluate the effectiveness of preoperative informational videos at improving the comprehension of informed consent content in bariatric surgery candidates. Materials and Methods A total of 74 bariatric surgery candidates were randomized into two groups. The first group was given a usual verbal-written informed consent. The second group got an additional informing video presentation informed consent, in addition to the usual verbal-written informed consent. Then, both groups got a questionnaire evaluating their knowledge of bariatric surgery informed consent. The correct response scores and their relationship with patient demographics were analyzed. Results Both groups had similar demographic features. Video-presented group had higher scores in questionnaire (11.3 +/- 2.3 versus 9.4 +/- 1.7, p = 0.001). Subgroup analysis showed that health care workers (12.5 +/- 1.9 versus 10.3 +/- 2.2, p = 0.005) and university graduates (11.6 +/- 2.4 versus 10.1 +/- 2.1, p = 0.03) got better results in the questionnaire. In multivariate analysis, video-assisted informing was found to be the only independent variable for high questionnaire scores (p = 0.0001). Conclusions This study showed that video-assisted informed consent improves patients' comprehension prior to bariatric surgery. We recommend routine preoperative video-assisted informing for bariatric surgery candidates in addition to usual verbal-written informed consent.