Autoimmune haemolytic anaemia (AIHA), immune thrombocytopenia (ITP) and autoimmune neutropenia (AIN) are well-recognised complications of allogeneic stem cell transplantation (SCT), but have previously only been reported in the context of myeloablative conditioning regimens. Management of AIHA, ITP or AIN occurring after allogeneic SCT is unsatisfactory since they frequently prove refractory to conventional therapies including splenectomy. As a consequence, autoimmune cytopenias occurring after allogeneic SCT are associated with substantial morbidity and mortality. We report four patients who developed AIHA or ITP after allogeneic transplantation -- three of which occurred after a reduced-intensity conditioning (RIC) regimen. All patients demonstrated a complete response to Rituximab, having failed to respond to conventional treatment including high-dose prednisolone and intravenous immunoglobulin (IVIg). We conclude that Rituximab can be a valuable agent in the management of autoimmune cytopenias occurring after allogeneic SCT and that autoimmune cytopenias may be a hitherto unrecognised complication of RIC regimens.