Epidemiologic studies on diabetes and body size in relation to risk of bladder cancer have yielded inconsistent results. We examined prospectively the associations between a history of diabetes, height, weight, body mass index and waist circumference, and the incidence of bladder cancer in the Cohort of Swedish Men, a prospective study of 45,906 men aged 45-79 years at baseline. During follow-up from 1998 through December 2007, 414 incident cases of bladder cancer were ascertained. A history of diabetes was not associated with risk of bladder cancer (multivariate rate ratio=1.16; 95% confidence interval=0.81-1.64). Similarly, no associations were observed for height, weight, body mass index or waist circumference. These findings in men do not support a role for diabetes, height or excess body mass in the aetiology of bladder cancer.