To compare functional and seizure outcomes in children with vascular and dysplastic etiologies of cerebral palsy and medically intractable epilepsy following functional hemispherotomy or anatomic hemispherectomy. Consecutive patients satisfying inclusion criteria from 07/01/2015 to 12/01/2019 were reviewed for demographic data and seizure (Engel classification) and functional (Functional Independence Measure for Children) outcomes. After a mean follow-up of 2 years 8 months (1 year 2 months), 11 of 18 patients achieved post-operative seizure freedom without significant difference between vascular (5/7) and dysplastic (6/11) etiologies (P = 0.64). Functional assessments were completed for 15 of 18 of subjects, split comparably between groups. Mean change in the Functional Independence Measure for Children from pre-operative baseline to inpatient rehabilitation admission (vascular, −35.3 13.2; malformation of cortical development{MCD}, −34.5 25.0; P = 0.69), inpatient rehabilitation admission to discharge (vascular, 18.7 9.0; MCD, 20.8 11.4; P = 0.60), and pre-operative evaluation to clinic follow-up (vascular, −7.6 9.7; MCD, −3.6 19.3; P = 0.61) did not differ between groups. Quantitative functional and seizure outcomes following functional hemispherotomy or anatomic hemispherectomy did not differ significantly between vascular and dysplastic etiologies of cerebral palsy and medically intractable epilepsy in this study. Hemispheric surgery resulted in minor functional declines from baseline following comprehensive multidisciplinary therapy.