Poly(epsilon-caprolactone) (PCL) electrospun nanofibers have been reported as a scaffold for tissue engineering application. However, high hydrophobicity of PCL limits use of functional scaffold. In this Study, PCL/polyethylenimine (PEI) blend electrospun nanofibers were prepared to overcome the limitation of PCL ones because the PEI as a cationic polymer can increase cell adhesion and can improve the electrospinnability of PCL. The structure, mechanical properties and biological activity of the PCL/PEI electrospun nanofibers were studied. The diameters of the PCL/PEI nanofibers ranged from 150.4 +/- 33 to 220.4 +/- 32 nm. The PCL/PEI nanofibers showed suitable mechanical properties with adequate porosity and increased hydrophilic behavior. The cell adhesion and cell proliferation of PCL nanofibers; were increased by blending with PEI due to the hydrophilic properties of PEI.