Numerous scaffolds that possess ideal characteristics for vascular grafts have been fabricated for clinical use. However, many of these scaffolds may not show consistent properties when they are exposed to physiologic vascular environments that include high pressure and flow, and they may eventually fail due to unexpected rapid degradation and low resistance to shear stress. There is a demand to develop a more durable scaffold that could withstand these conditions until vascular tissue matures in vivo. In this study, vascular scaffolds composed of poly(epsilon-caprolactone) (PCL) and collagen were fabricated by electrospinning. Morphological, biomechanical, and biological properties of these composite scaffolds were examined. The PCL/collagen composite scaffolds, with fiber diameters of approximately 520 nm, possessed appropriate tensile strength (4.0+/-0.4 MPa) and adequate elasticity (2.7+/-1.2 MPa). The burst pressure of the composite scaffolds was 4912+/-155 mmHg, which is much greater than that of the PCL-only scaffolds (914+/-130 mmHg) and native vessels. The composite scaffolds seeded with bovine endothelial cells (bECs) and smooth muscle cells (bSMCs) showed the formation of a confluent layer of bECs on the lumen and bSMCs on the outer surface of the scaffold. The PCL/collagen composite scaffolds are biocompatible, possess biomechanical properties that resist high degrees of pressurized flow over long term, and provide a favorable environment that supports the growth of vascular cells.