OBJECTIVE In men with urinary incontinence from idiopathic detrusor overactivity we determined whether bladder voiding dynamics differs between those with and without urgent micturition. METHODS We retrospectively assessed urodynamic findings in 3 groups of 22 men each. Groups 1 and 2 had idiopathic detrusor overactivity with detrusor overactivity incontinence and with micturition urgency in group 1. Group 2 showed no urgency but felt a strong voiding desire just after the onset of involuntary micturition. Control group 3 included nonneurological unobstructed men undergoing urodynamic examination for mixed reasons who proved to be urodynamically normal. Patients with detrusor overactivity and controls were assessed by nonparametric statistics for significant differences in bladder voiding dynamics. RESULTS Detrusor contraction strength proved to be increased in groups 1 and 2 with the highest levels in group 1. Detrusor contraction velocity had the highest levels in group 1 and it differed insignificantly in groups 2 and 3. Voiding contractions were equally well sustained in groups 1 and 3, and proved to be less well sustained in group 2. CONCLUSIONS Detrusor overactivity involves enhanced detrusor contraction strength levels, particularly in patients who feel urgency. In urgency-free patients with detrusor overactivity detrusor contraction velocity differs insignificantly from that in controls and voiding detrusor contractions proved to be less well sustained than in controls and patients who experienced urgency. This suggests that detrusor contraction velocity may have a role in causing urgency and urgency may have a role in enhancing and sustaining involuntary voiding detrusor contractions in patients with detrusor overactivity.