Purpose -The aim of this study is to test the hypothesis that Clozapine reduces rates of self injury and the use of restraint in a medium secure setting in female patients who have a diagnosis of borderline personality disorder (BPD) and mild learning disability.Design/methodology/approach -A retrospective method of data collection was used with a requirement of six months baseline data on rates of self injury and the use of restraint. Patients were required to remain on Clozapine for a minimum of six months.Findings -The mean number of incidents of self injury in the six months prior to Clozapine was 20.75 (SD 8.8) and 13.5 (SD 4.51) in the six months following Clozapine, a reduction of 35 per cent. The mean number of incidents of restraint in the six months prior to Clozapine was 17.75 (SD 6.86) compared with 9.25 (SD 4.96) in the six months following commencement of Clozapine therapy, a reduction of 48 per cent. The results were analysed using the paired t-test and the difference between the means (self injury and use of restraint) was not statistically significant. This study demonstrates a reduction in the rates of self injury and use of restraint in women with a diagnosis of BPD when treated with Clozapine which was clinically significant although not statistically significant.Originality/value -The authors are not aware of any published articles on the use of Clozapine in women with BPD and co-morbid learning disability.