The purpose of this study was to retrospectively evaluate the cognitive and electroclinical characteristics of right cerebral hemiatrophy (Dyke-Davidoff-Masson syndrome [DDMS]). Cognitive assessments with a particular emphasis on visuospatial functions, electroclinical features, and neuroimaging characteristics were analyzed for five patients with a clinically and neuroradiologically confirmed diagnosis of right-sided DDMS. Intelligence tests revealed mental retardation in all but one. Neuropsychological assessments demonstrated consistent impairments in tasks that have a spatial component (spatial processing and orientation discrimination), whereas attention, executive functions and verbal memory domains were variably impaired. Electroclinically, the main seizure types were simple partial motor, complex partial, and secondarily generalized seizures. Interictal EEG delineated lower amplitudes and slow background activity in the affected hemisphere. Overall, the cognitive performance of patients with DDMS encompasses a broad spectrum of impairments affecting multiple domains. Our findings support the concept that dorsal visual pathways responsible for spatial processing may be lateralized to the right hemisphere.