PURPOSE:: We investigated whether certain voiding problems have a higher incidence in patients with attention deficit disorder with hyperactivity compared to age matched controls. MATERIALS AND METHODS:: We used the Conners Parent Rating Scale-revised for attention deficit disorder with hyperactivity and lower urinary tract symptom score to evaluate voiding problems. A total of 62 children with attention deficit disorder and 124 healthy controls were enrolled. We evaluated uroflowmetry patterns in both groups. Residual urine volumes and Bristol stool scale were noted. We examined the correlation between total Conners Parent Rating Scale-revised and lower urinary tract symptom score in patients with attention deficit disorder. Additionally we analyzed each index of the Conners Parent Rating Scale-revised separately in terms of correlation with symptom subgroups for lower urinary tract symptom scores. RESULTS:: Mean ± SD total lower urinary tract symptom score was 11.1 ± 2.9 in patients with attention deficit disorder with hyperactivity and 3.2 ± 1.3 in controls, a difference that was statistically significantly (p <0.001). With the exception of constipation, mean scores of all lower urinary tract symptom subindices were significantly higher in patients with attention deficit disorder compared to controls. Symptoms evaluated in lower urinary tract symptom score were mostly correlated with attention deficit disorder index of the Conners Parent Rating Scale-revised. If a child with attention deficit disorder has a high index in the Conners Parent Rating Scale-revised, he or she is more likely to have urgency. Also, if a child with attention deficit disorder has a high hyperactivity subscale score, he or she is more likely to have enuresis. CONCLUSIONS:: Voiding problems are more common in children with attention deficit disorder with hyperactivity than in age matched controls. Urgency and enuresis are the outstanding problems in children with attention deficit disorder. Simultaneous use of the Conners Parent Rating Scale-revised and lower urinary tract symptom score questionnaire should be encouraged in patients with attention deficit disorder to allow a structured and quantitative evaluation of these overlapping problems.