Hemophilia A is an inherited bleeding disorder caused by deficiency of coagulation factor VIII. It is transmitted in an X-linked recessive pattern from female carriers to male children. We report the observation of a severe hemophilia A in a male newborn with a history of hemophilia in the siblings who present hemarthrosis of the left elbow. The diagnosis was suspected and confirmed through biologic investigations and imaging. Therefore, patient was put under factor VIII with good evolution. It is a congenital hemorrhagic disease related to deficiency in anti-hemophilic factor. The severity of the bleeding syndrome is correlated to the factor level. There are three varieties of hemophilia: severe, moderate and minor. The main complications are hemarthrosis, hematomas of variable location and externalized hemorrhages. A favorable prognosis depends on rapid diagnosis, monitoring and immediate medical treatment. Diagnosis of hemophilia A should be rule out in all male newborns with a family history of hemophilia, and suspected in the presence of cord bleeding at birth or during circumcision.