Purpose: To identify factors related to changes in foot status and foot care in patients with diabetes mellitus participating in an exercise program. Methods: The subjects were 21 patients with Type 2 diabetes mellitus (8 males, 13 females). The mean age of the patients was 62.3 ± 12.5 years old. Foot status, physical measurements and daily activities were monitored and several surveys were performed. Results: Changes in foot status were significantly positively correlated with walking at normal speed (r = 0.54, p < 0.05) and fast speed (r = 0.68, p < 0.01), and significantly negatively correlated with foot care (r = −0.51, p < 0.05). Foot care showed a significant negative correlation with burden of diet therapy (r = −0.48, p < 0.05) and a significant positive correlation with the self-efficacy of diet therapy (r = 0.65, p < 0.01). Conclusions: Subjects who were fast walkers showed greater changes in foot status. Poor foot care behavior is also related to greater changes in foot status. Regular interventions for foot care are important to improve self-care behavior during an exercise program.