The association of urinary cytokine concentration with the incidence of urinary tract infection in patients with diabetes mellitus was explored. Urinary interleakin-6 (IL-6) level in 156 female type 2 diabetes mellitus patients was tested and followed up for 6 months. The incidence of urinary tract infection between the top quartile of baseline urinary cytokine concentration with the bottom quartile was compared. The incidence of top quartile of urinary IL-6 concentration at baseline was significantly lower than that of bottom quartile ( 13.5% vs 37.8%, P<0.05 ). Abnormality of urinary IL-6 concentration may be involved in the mechanism leading to higher prevalence of urinary tract infection in patients with diabetes mellitus.