A group of 75 mildly to moderately mentally handicapped people with epilepsy, resident in both a hospital and the community, were studied together with an individually matched control group of non-epileptic patients. Their carers were interviewed to gather information for two observer-rated personality questionnaires, the Standardised Assessment of Personality (SAP) and the T-L Personality Behaviour Inventory. The two groups were compared with respect to the prevalence rates of various personalities. An abnormal personality score according to the SAP schedule was reported in 26% (n = 39) of the cohort, of which 28 (18.6% of the cohort) were personality disorders. A diagnosis of SAP abnormal personality was made in 46% of the in-patients and 6.5% of the community-based population. Of the cohort, 15% had an abnormal personality score according to the T-L schedule. No statistically significant difference emerged between the epileptic and the non-epileptic groups in the prevalence of either the SAP or T-L personality.