Background: This study aims to evaluate differences in the clinical profiles and use of psychiatric services by people with schizophrenia with and without borderline intellectual functioning. Both groups in this study were receiving standard community psychiatric care. Methods: A naturalistic sample of 372 people with schizophrenia completed the National Adult Reading Test. Data were collected prospectively over 18 months on psychiatric symptoms and service use. Three hundred and thirteen had normal intellectual functioning (mean age 43, range 20-76 years) and 59 had borderline or lower intellectual functioning (mean age 45, range 21-81 years). This was defined by a National Adult Reading Test error score of more than 40. Results: People with borderline or lower intellectual functioning had a lower quality of life, more severe psychotic symptoms, reduced functioning and fewer antidepressant prescriptions. There were no significant differences in service use including hospital admission. Conclusions: People with schizophrenia and borderline or lower intellectual functioning are a more disabled group within general adult psychiatric services who should be the focus of initiatives for improved service delivery.