This study examines the usefulness of the Brief Symptom Inventory (BSI) as a screening tool for psychological disorders in patients with epilepsy and mild intellectual disabilities. Participants were 91 residents of the Bethel Institute, Bielefeld, Germany. Cronbach’s α was revealed to be sufficient for the composite score Global Severity Index (GSI) (0.95) and for most of the subscales (0.64–0.80). Compared with normative data, residents with epilepsy scored slightly higher on all BSI scales. Only the subscale Paranoid Ideation was especially elevated, a finding of heuristic value. Subgroups of residents with past psychiatric morbidity, on current psychotropic medication, with poor seizure control, and more epilepsy-related problems either tended toward or demonstrated higher GSI scores. These results indicate the validity of the questionnaire with the GSI as a global indicator of possible psychopathology. BSI subscales seemed to reflect predominantly the amount of emotional distress, but their potential to identify specific clinical syndromes remained unclear.