Recent studies have clarified that at least 25% of patients with type 2 diabetes have low free testosterone levels with low luteinizing hormone and follicle stimulating hormone levels, and another 4% have low free testosterone with high luteinizing hormone and follicle stimulating hormone levels. Therefore, the American College of Endocrinology currently recommends routine measurement of testosterone levels in patients with type 2 diabetes. Low testosterone levels are not associated with glycated hemoglobin and duration of diabetes, but with obesity, high levels of C-reactive protein, and moderate anemia. In addition, 2 earlier studies found that patients with type 2 diabetes who had lower than normal testosterone levels had a 2-3 fold increased risk of cardiovascular events and death. Short-term studies of testosterone replacement therapy have confirmed that testosterone replacement therapy facilitates glycemic control, lowers triglyceride levels, and improves libido but does not significantly help with erectile function; therefore, the use of phosphodiesterase 5 inhibitors such as Cialis may be needed to improve erectile function.