Haemorrhagic cystitis (HC) after allogeneic haematopoietic stem cell transplantation (HSCT) or high-dose cyclophosphamide (CP) chemotherapy is a severe side-effect and can cause significant morbidity and mortality. In this report, we describe the clinical courses of 10 patients with HC and review the literature. The patients were treated with oral conjugated estrogen in an attempt to improve severe haemorrhagic cystitis. In seven patients positive effects were seen, haematuria resolved in all, but residual symptoms of dysuria remained for longer periods. In one patient application of estrogen was interrupted because of hepatotoxicity. Two patients failed all treatment modalities including oral estrogen because of terminal illness. We conclude that in the management of HC the administration of oral conjugated estrogen should be considered.