Vascular manipulation is performed for various purposes, which can often lead to complications. Complications can also occur in normal people, but hemophilia, coagulopathy, and taking anticoagulants may be particularly risk factors. Hemophilia, a hereditary disease, is a serious hemorrhagic disease caused by a lack of coagulation factors involved in the blood coagulation process. We describe various vessel-related complications, including pseudoaneurysms, neuropathy after vascular catheterization, and uncontrolled bleeding after angiography in hemophilia patients. First, pseudoaneurysms occurred to 3 hemophilia patients after radial arterial puncture. Two cases of pseudoaneurysms developed after arterial sampling in hemophilia neonates and one case was due to arterial line procedure. All cases were diagnosed by ultrasonography. They all received conservative management such as clotting factor replacement or sono-guided compression, and improved. Secondly, neuropathy can occur as a complication of blood sampling and hematoma after blood sampling. An 8 - month – old boy, who was admitted due to hematoma after sampling from antecubital area, was diagnosed with hemophilia A. Hematoma improved with clotting factor, but motor and sensory deficit at the affected arm developed and neuropathy was confirmed by electromyography. Lastly, there was a case of mortality. A hemophilia patient with inhibitor developed hemothorax due to the massive bleeding of intercostal artery and arterial embolization was done. However, he developed uncontrollable bleeding at the puncture site, which eventually led to the patient’s death. In hemophilia patients, vascular manipulations require more attention. Before complications arise, prevention such as sufficient coagulation factors and skilled procedure is needed. Early detection and immediate approach are critical because they can lead to death due to possible complications. In conclusion, if there is a bleeding tendency, careful management should be taken even before diagnosed with hemophilia.