a Background The levonorgestrel-releasing intrauterine system (LNG-IUS) is used commonly by gynaecologists as a contraceptive and to treat menorrhagia. However, its efficacy has not been examined in women with inherited bleeding disorders. Design A prospective pilot study.Setting A teaching hospital in north London with a designated haemophilia centre.Population Female patients with a known inherited bleeding disorder.Methods Sixteen women with subjective and objective menorrhagia caused by inherited bleeding disorders (13 von Willebrand's Disease, two factor XI deficiency and one Hermansky -Pudlak syndrome), who had previously undergone unsuccessful medical treatment were followed up for nine months after LNG-IUS insertion. Bleeding was measured by pictorial chart and haemoglobin concentration. Results All women reported that their periods were improved, pictorial chart scores were lower and 56% became amenorrhoeic. None reported side effects. Conclusion The LNG-IUS is well tolerated and effective and improves quality of life.