Hypercoagulable state is well recognized in patients with β-thalassemia. Evidences of hypercoagulability include abnormal expression of phosphatidylserine on red blood cell (rbc) surface and consequent increased platelet activation and thrombin generation. In addition, a reduction of anticoagulants i.e. proteins C and S and antithrombin (AT) was demonstrated. However, coagulable state in patients with β-thalassemia following stem cell transplantation (SCT) has not been characterized.Therefore, the objective is to compare coagulation markers and anticoagulants among β-thalassemics with and without SCT and normal control (NC).The subjects will be classified into 3 groups; β-thalassemia post SCT (Thal-SCT), β-thalassemia treated with regular transfusion (Thal-RT) and NC. Blood samples will be tested for annexin V (an index of abnormal expression of phosphatidylserine on rbc surface), markers of activation of coagulation system (thrombin antithrombin complex (TAT), prothrombin fragment (F1+2), and D-dimer) and anticoagulants (proteins C and S and AT).