Twenty seven right-handed subjects aged 7-30 years with the attention deficit/hyperactivity disorder (ADHD) were exposed to standard MRI examination. From them, 14 were younger than 13 years old. The volumes of lateral ventricles were measured using T1-weighted MR-images of the sagittal brain sections to within 3 mm3. External head radii were measured additionally to normalize ventricle volumes. All patients passed complex neuropsychological testing. Memory and functions of visual, auditory, tactile and spatial recognition, motor and speech spheres were examined. Test results were evaluated by the degree of disorders with reference to corresponding brain structures on a 10-point scale. Absence of disorders corresponded to 0 points and maximum intensity of was scored as 10. Disorder scores were summed up for each of hemispheres, the first area (cortical structures), and all structures. Neuropsychological testing revealed disorders, predominantly, in the frontal area, hippocampus and reticular formation. Neuropsychological deficit was minimally related to the disturbances in post-central and parietal cortical areas. Statistical analysis revealed significant positive correlation between normalized volume of the left lateral ventricle and neuropsychological disorder score (r = 0.5127, p = 0.0063) for the whole group studied. The correlation between the normalized volume of the left lateral ventricle with the disorder score related to the left hemisphere was more significant (r = 0.6303, p = 0.0004). At the same time, a correlation of the ventricle volume and the dysfunction of the cortical structures was revealed (r = 0.5071, p = 0.0069) in subjects younger than 13 years old. The study corroborated interrelation between the volume of ventricles and linear head dimensions (r = = 0.5759, p = 0.0017) which was more pronounced in younger subjects (r = 0.6833, p = 0.01).