Treatment with antipsychotics is a common approach for personality disorder. Conventional antipsychotics may be efficacious particularly against psychoticism, but less against other symptoms in these patients. They are, furthermore, associated with adverse drug reactions poorly tolerated by patients with personality disorder. Atypical antipsychotics have a more convenient pharmacological profile with a lower risk for extrapyramidal symptoms and a broader therapeutic profile, showing some efficacy against impulsivity, aggressivity and affective symptoms. The medical records of ten patients with a DSM-IV diagnosis of a cluster B personality disorder who had received olanzapine treatment were reviewed. A mirror-image design anchored to the start date of olanzapine treatment and extending 8 weeks in either direction was used. The assessment consisted of a qualitative chart review and a retrospective completion of the GCI-C and an adapted French version of the SDAS, using the observer-rated items. The olanzapine dose range was 2.5-20 mg during the 8 weeks of observation. The mean SDAS score (items 1-15) was 28.8+/-8.4 for the 8 weeks preceding olanzapine prescription and was improved to 13.6+/-5.8 after 8 weeks of treatment.