ABSTRACT Electrospun nanofibers of poly (2‐methacryloyloxyethyl phosphorylcholine) (MPC) possessing excellent hemocompatibility were successfully fabricated first. These nanofibers were investigated as drug‐delivery vehicles for suppressing the acute thrombogenicity of vascular grafts to lower the risk of coronary artery disease by improving the graft patency rate; the graft patency rate is the percentage of patients who do not have any blockage in a graft after a stent‐graft treatment. We varied the MPC concentrations in ethanol from 1 to 10 wt % to fabricate electrospun MPC fibers. Scanning electron microscopy images revealed that when the MPC concentration was lower than 5 wt %, beads instead of fibers were formed. When the MPC concentration was increased (>5 wt %), uniform fibers were produced with average fiber diameters of about 160 nm (5 wt %), 640 nm (7.5 wt %), and 1270 nm (10 wt %). In vitro drug‐release tests showed that a higher amount of drugs was diffused from MPC fibers with small diameters; this indicated a faster drug‐release rate for the thinner MPC fibers. Diameter‐controlled MPC fibers could be used as a new vascular graft materials. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40606.