Escherichia coli is the major pathogen in many extraintestinal Gram-negative bacillus infections. Several virulence factors of E. coli are responsible for colonization and invasion of the host, and/or serve to avoid or disrupt host defense mechanisms. Both E. coli virulence characteristics and host factors contribute to the development of E. coli bacteremia in upper urinary tract infection (UTI). Patients with diabetes mellitus have an increased risk for infections, including UTI, soft tissue infections, communityacquired pneumonia, necrotizing otitis externa, and bloodstream infections. Impaired host defense, in both cell-mediated immunity and humoral immunity, increases the susceptibility to infection. Diabetes-associated functional and anatomical abnormalities of the host also contribute to it. Poor glycemic control increases the risk of community-acquired infections and acquiring asymptomatic bacteriuria (ABU). Diabetes with poor glycemic control and urinary tract obstruction are important host factors predisposing to emphysematous pyelonephritis. In most E. coli extraintestinal infections, host immunocompetence is associated with a relatively high prevalence of papG II, afa and iha, and relatively low antimicrobial resistance to fluoroquinolones. The role of bacterial characteristics and glycemic control in diabetic patients with E. coli infections related to urinary tract has not been well investigated. The aims of this study were to examine and compare the bacterial characteristics and glycemic control in diabetic patients with E. coli infections arising in the urinary tract.