We screened 228 women with diabetes for bacteriuria during the period of January 1997 through December 2000 at Pisa General Hospital (Pisa, Italy). A control group of 146 women without diabetes was also evaluated. The frequency of significant bacteriuria was 17.5% (40 of 228) among women with diabetes and 18.5% (27 of 146) among women in the control group. Seven (13.5%) of 52 and 33 (18.8%) of 176 women with type 1 and in type 2 diabetes, respectively, had significant bacteriuria. The presence of higher glycated hemoglobin levels was the only significant risk factor for significant bacteriuria in women with type 2 diabetes. A similar frequency of bacteriuria in women with and women without diabetes was found. Severe impairment of metabolic control of type 2 diabetes increases the risk of acquiring asymptomatic bacteriuria.