Ion implantation into collagen coated inner surface of the test tube with a diameter of 2 and 3 mm, length of 50 mm was performed to develop the hybrid type small diameter artificial vascular grafts. Substrates used were polystyrene tubes with a inner diameter of 2 mm and polytetrafluoroethylene (ePTFE) tubes with a inner diameter of 3 mm. Ne + ion implantation at an energy of 150 keV with a fluence of 3 × 10 15 ions/cm 2 was performed as a pre-treatment of protein coating. Ion implanted test tubes were coated with collagen (type I). He + , Ne + and Kr + ion implantation into inner surface of collagen coated tubes were performed at an energy of 150 keV with a fluence of 1 × 10 14 ions/cm 2 . Grafts were exposed to blood for one hour up to 120 days. He + ion implanted collagen coated specimens exhibit cell attachment and inhibition of platelet adhesion. Replaced He + ion implanted collagen coated grafts with carotid artery demonstrated 100% patency for 120 days. In contrast, Ne + and Kr + ion implanted grafts were occluded. He + ion broke the ligand which corresponds to platelet and the ligands corresponding to endothelial cell were still existent after ion implantation. Ion implantation technology into inner surface of the collagen coated test tube may develop a new small diameter artificial vascular grafts.