Voiding difficulty has been relatively overlooked as a diagnosis. Previous estimates of its prevalence have generally been no more than 14% with one exception at 24%. The aim of this study is to determine the true prevalence and associations of voiding difficulty using a validated definition [urine flow rate under 10th centile of the Liverpool Nomograms and/or residual urine volume (by transvaginal ultrasound) more than 30 ml]. This study involved 592 women referred for an initial urogynecological assessment including urodynamics. Data were separated according to the presence or absence of voiding difficulty. The prevalence of voiding difficulty was 39%, far higher than previous estimates. It is the third most common urodynamic diagnosis behind urodynamic stress incontinence (USI-72%) and uterine/vaginal prolapse (61%) and ahead of the overactive bladder (13%). Voiding difficulty significantly increased in prevalence with age and increasing grades of all types of uterine/vaginal prolapse. Prolapse appeared to be the main factor in the age deterioration. Other significant positive relationships with voiding difficulty were prior hysterectomy and prior continence surgery, whilst USI and the symptom and sign of stress incontinence had significant inverse relationships.