Infection is one of the major causes of fatality in the diabetics. The diabetics have an increased frequency of infection which is more severe and protracted in such individuals. Two major possibilities have been considered as the main contributing factors to infection in diabetes mellitus. The first, the defects in host resistance including vascular insufficiency, peripheral neuropathy and immune defense abnormalities cause the diabetics susceptible to infections. The second, the environment in the body of the diabetics is in favor of particular pathogens to grow. In this brief report, infections involved in specific pathogens and organs in the diabetics are reviewed. In addition, underlying defects in the immune defense mechanisms and leukocyte functions of the diabetics are discussed.