Purpose Diabetic foot is a serious and preventable complication. Foot self-inspection is one of the most important foot care behaviors to prevent diabetic foot. This experimental study aimed to assess the effect of using a reminder diabetic foot mirror on foot checking frequency and development of diabetic foot. Methods This research was carried out between May 2019 and February 2020 at a university hospital in Istanbul. In this study, 133 people with diabetes were included and assigned to groups randomly. A reminder diabetic foot mirror was given to the experimental group 1, while the diabetic foot mirror was given to the experimental group 2. Diabetic foot examinations were performed at the beginning of the study and every 3 months. For 9 months, foot examination frequency data were recorded by interviewing the participants at the end of each month. Results At the beginning of the study, the participants in all the groups had similar characteristics. However, at the end, it was found that the frequency of foot checking was higher in people with diabetes who used a reminder diabetic foot mirror when compared with those who did not, and this difference was statistically significant (p < 0.05). While none of the participants developed diabetic foot, it was found that the use of a reminder diabetic foot mirror led to positive changes in temperature, hydration, edema, and interdigital assessments in foot examination. Conclusion Using a reminder diabetic foot mirror is an effective approach to increase the frequency of foot checking in people with diabetes.