Aplastic anemia is a rare side-effect associated with ticlopidine therapy. We report two cases of severe aplastic anemia developed after the use of ticlopidine. A 51-year-old woman took ticlopidine at 500 mg/day for 49 days to prevent a secondary stroke. She developed fever and dizziness within 49 days of initiating ticlopidine therapy. A 70-year-old woman was started on ticlopidine after coronary stent insertion. Fifty days after starting ticlopidine, she developed fever and dizziness. Both patients showed pancytopenia and were diagnosed as aplastic anemia which were confirmed by bone marrow examination. Both patients were hospitalized and received antibiotics, blood products and hematopoietic growth factors. Four and seven weeks after the withdrawal of ticlopidine, the hematologic parameters of each patient improved. A complete blood count should be monitored during ticlopidine therapy to check for cytopenia.