Electrospun polymer nanofibers demonstrate great potential in the field of tissue engineering due to their favorable geometric characteristics and versatility for biofunctionalization. Appropriate surface functionalization of nanofiber scaffolds can result in improved cell interactions such as attachment and proliferation. Here a simple method of introducing functional groups to electrospun scaffolds by blending amine terminated block polymer chains directly into an electrospinning solution is investigated. This method benefits from simplicity and does not require any harsh physical or chemical treatments that may damage nanofiber structures. The potential of this method in vascular graft applications was demonstrated by attaching heparin to the surface of electrospun polyurethane scaffolds. Heparin incorporation was confirmed by toluidine blue assay and X-ray photoelectron spectroscopy. Bioactivity of the functionalized scaffolds was demonstrated by improved endothelial cell attachment in vitro.