['To assess overactive bladder and its component symptoms among patients with type 2 diabetes mellitus and to explore whether higher glycosylated hemoglobin and other factors increase the risk of overactive bladder symptoms.', 'A total of 279 diabetes mellitus patients from our outpatient clinic, and 578 age- and sex-matched subjects without diabetes mellitus from public health centers were enrolled from May to September of 2010. The collected data included overactive bladder and its component symptoms measured by using the Overactive Bladder Symptom Score, and collecting demographic and clinical data. Overactive bladder was defined as total Overactive Bladder Symptom Score ≥3 and urgency score ≥2 (once a week or more).', 'Diabetes mellitus patients had a significantly higher proportion of overactive bladder symptoms/urgency compared with the controls (28.0% vs 16.3%, odds ratio 2.03, 95% confidence interval 1.44-2.86), as well as nocturia (48.0% vs 39.1%, odds ratio 1.44, 95% confidence interval 1.08-1.93). There were no significant effects of diabetes mellitus on urge urinary incontinence (14.0% vs 10.9%, odds ratio 1.32, 95% confidence interval 0.86-2.04) and daytime frequency (26.9% vs 32.4%, odds ratio 0.77, 95% confidence interval 0.56-1.05). After adjusting for all variables, high glycosylated hemoglobin levels were significantly associated with overactive bladder/urgency (odds ratio 1.24, 95% confidence interval 1.06-1.45), urge urinary incontinence (odds ratio 1.20, 95% confidence interval 1.00-1.45) and nocturia (odds ratio 1.17, 95% confidence interval 1.01-1.35).'] Do higher glycosylated hemoglobin levels increase the risk of overactive bladder syndrome in patients with type 2 diabetes mellitus?