Homozygous protein C deficiency is a rare hereditary coagulation disorder that occurs most often in childhood and is characterized by widespread thrombosis of capillaries and venules, abrupt onset of ecchymoses and necrosis. The hematological feature corresponds with disseminated intravascular coagulation. Protein C is a natural anticoagulant and also has important anti-inflammatory activity. For confirmation of homozygous protein C deficiency, the infant should have undetectable protein C activity and both parents should be heterozygous for protein C deficiency. We experienced a case of purpura fulminans in the newborn infant in whom we identifed homozygosity for familial protein C deficiency. Fresh frozen plasma for replacement of protein C, early debridement and full-thickness skin graft induced a remission. Administration of warfarin was used to prevent recurrence of attacks. This report emphasizes the need for early diagnosis and adequate replacement therapy in patient with purpura fulminans. (Korean J Dermatol 2002;40(1)：38~43)