We experienced a 3 months infant with thalamic hemorrhage penetrating to lateral ventricle with abnormal Protein S. Although the coagulation factor and fibrinogenolysis factors were evaluated, there were no remarkable abnormal laboratory data except for slightly decline of Protein S. The DNA analysis was performed for Protein S, and a missense mutation(A to G transmission) was found, which was resulting in Lys-155 to Glu. The total Protein S antigen was normal level, but co-factor activity for activated Protein C was declined. That mutation is named Protein S-Tokushima, and the patient who has abnormal Protein S tends to suffer recurrent coagulopathy. In our patient, it was interesting that any thrombotic disease had not occurred, but cerebral hemorrhage had occurred.