Thrombocytopenia is common during the early posttransplant period. Most cases are mild and recover in 1 month. Occasionally, severe thrombocytopenia may occur in the late posttransplant period. We report a 10-year-old boy with severe thrombocytopenia 3.5 years after liver transplant. We exclude secondary causes of thrombocytopenia. Bone marrow aspiration findings and treatment response were suggestive for immune thrombocytopenic purpura. The patient was treated with intravenous immunoglobulin at thrombocytopenia periods successfully. We continued tacrolimus, but preferred a reduced dose. In conclusion, immune thrombocytopenic purpura should be borne in mind as a reason of late onset, severe thrombocytopenia after liver transplant.