Frequency of comorbid disorders and neuropsychological state, executive functions (EF), were studied in two groups of patients aged from 5 to 14 years: 53 patients with attention-deficit hyperactivity disorder (ADHD) in the association with enuresis and 71 patients with ADHD without enuresis. The most cases of enuresis (50 out of 53 patients) were represented by primary nocturnal enuresis. The significant increase of total number of ADHD cases with comorbidity for oppositional-defiant disorder, anxiety disorder, tics or encopresis (77.7%) was found in the first group compared to the second one (60.6%). The presence of enuresis in ADHD was associated with the significant increase of frequency of anxiety disorders (54.7% versus 39.4%). Moreover, in the group of patients with ADHD and enuresis, the frequency of oppositional-defiant disorder and encopresis was higher in the age of 5-9 years while the frequency of obsessive-compulsive disorder and tics increased in the period of 10-14 years as compared to patients without enuresis. The assessment of executive functions with the Wisconsin Card Sorting Test did not reveal any differences between patients of two groups.