Exercise is an effective treatment for type 2 diabetes mellitus, resulting in stabilization of plasma glucose in the acute phase and improvements in body composition, insulin resistance and glycosylated haemoglobin with chronic exercise training. However, the most appropriate exercise prescription for type 2 diabetes has not yet been established, resulting from insufficient evidence to determine the optimum type, intensity, duration or frequency of exercise training. Furthermore, patient engagement in exercise is suboptimal. There are many likely reasons for low engagement in exercise; one possible contributory factor may be a tendency for expert bodies to prioritize the roles of diet and medication over exercise in their treatment guidelines. Published treatment guidelines vary in their approach to exercise training, but most agencies suggest that people with type 2 diabetes engage in 150 min of moderate to vigorous aerobic exercise per week. This prescription is similar to the established guidelines for cardiovascular health in the general population. Future possibilities in this area include investigation of the physiological effects and practical benefits of exercise training of different intensities in type 2 diabetes, and the use of individualized prescription to maximize the health benefits of training.