Objective:To summarize the clinical characters of severe bone marrow suppression after liver transplantation and find effective measures to prevent severe bone marrow suppression occurring. Methods:The clinical data of 6 cases of severe bone marrow suppression after liver transplantation occurred between 2002 and 2006 in Tianjin First Central Hospital were analyzed retrospectively. Results:All patients received standard immunosuppressive protocols for liver transplantation,including a combination of tacrolimus,mycophenolate mofetil (MMF) and steroid.Ganciclovir was used for prophylaxis cytomegalovirus in each case.Severe bone marrow suppression (white blood cell count<10×109/L ) occurred from 19 to 78 days after transplantation.Clinical manifestations included fever,nausea,skin rash,infection even to sepsis.Liver functions of case 1 to 5 were almost normal until to dead.All patients were dead of severe sepsis and multiple system organ failure. Conclusion:Severe bone marrow suppression after liver transplantation maybe relates to immune reaction,drug toxicity,severe infection or other reasons.The incidence and accurate pathogenesis are unclear.Once severe bone marrow suppression occurred,the prognosis is very poor.It’s important to take effective measures to prevent severe bone marrow suppression occurring.