Background: People with diabetes report that diabetes affects particular aspects of their marital life and leads to other problems in their lives. Moreover, the self-efficacy of diabetic patients is affected by their disease in various respects. There is a significant relationship between self-efficacy and health behaviors. Objectives: This study was conducted to determine the effect of audiovisual education on self-efficacy toward marriage in single people with type 1 diabetes. Methods: This randomized, controlled trial study was carried out on 100 unmarried patients with type 1 diabetes visiting Iran's diabetes society in 2015-2016. The convenient sampling method was used in this study. Samples were divided into two groups (50 patients in each group) with a simple, randomized sampling method. The data collecting tool was a researcher-made questionnaire that patients completed before the intervention and eight weeks afterwards. The intervention was an educational CD about improving self-efficacy toward marriage in diabetics. Using descriptive statistics, inferential statistics (i.e., chi-square, t-test, paired t, Fisher, and co-variance tests), and SPSS software version 16, the self-efficacy toward marriage in both the intervention and control groups was compared. A significant level was considered less than 0.05. Results: The mean of the self-efficacy score improved significantly in the intervention group (84.14 ± 16.29 to 105.82 ± 5.49, P < 0.001). However, this score decreased in the control group (92.92 ± 12.33 to 86.48 ± 11.54, P < 0.001). In addition, the self-efficacy in the control group was higher than in the intervention group before the study (P = 0.003), although the score of the intervention group significantly increased after the study (P < 0.001). Conclusions: This study showed that audiovisual training can have a significant effect on the self-efficacy of people with type 1 diabetes. Providing audiovisual equipment to referral centers of type 1 diabetics, such as hospitals, health centers, and clinics, as well as informing related officials, can be of benefit to managers.