Authors present the case report of the pseudoaneurysm of deep femoral artery caused by the injury of the vessel wall during the open femur fracture. This fracture was primarly treated by repoisition and stabilization by the external fixator (Rohr system, Synthes GmbH, Switzerland), which was nine days later converted into the intramedullar osteosynthesis by the unreamed nail UFN (Synthes GmbH, Switzerland). The first clinical signs of the pseudoaneurysm occurred several days after the patient had been dismissed. In the clinical picture there dominated the painful swelling of thigh but no perfusion or innervation disorders in the periphery of the extremity were noticed and the finding was concluded as myositis ossificans. Proper diagnosis was set only 6 weeks later on the basis of the ultrasound and angiographic investigations. The situation was then solved by the angiographic embolization of pseudoaneurysm. In the discussion also other opinions from the literature are presented.