A relapsing clinical syndrome of skin lesions and disseminated intravascular coagulation (DIC) that showed remission with the infusion of fresh frozen plasma is described in a newborn infant with homozygous deficiency of protein C antigen. This patient presented since birth a recurrent clinical picture of DIC and ecchymotic skin lesions that resembled typical ecchymosis except for the fact that they showed immediate improvement with the administration of fresh frozen plasma. Using an enzyme linked immunosorbent assay method, the determination of protein C antigen levels in the patient, without ingestion of coumarin drugs, showed very low values (less than 1%). No other deficiencies in the vitamin-K-dependent factors or in antithrombin III, antiplasmin, and plasminogen were found. Seven relatives of the infant had heterozygous deficiency in protein C antigen (values between 40-55%), without clinical history of venous thrombosis. The pedigree analysis of this family suggests an autosomal recessive pattern of inheritance for the clinical phenotype, although an autosomal dominant pattern has been postulated until now in other reported families. We conclude that our patient has a homozygous deficiency in protein C and this homozygous state may be compatible with survival beyond the neonatal period.