Electrospinning is one of the fabrication method to form ultra-fine fiber in a nano-scale made of synthetic and natural extracellular matrix components for tissue-engineering applications. In this study, a nanofibrous scaffold was obtained by co-electrospinning poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and gelatin in 2,2,2-trifluoroethanol (TFE) at a ratio of 50/50. The resulting fiber diameters were in the range of 400-1,000 nm without any beads. The nanofiber surfaces were characterized by attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), electron spectroscopy for chemical analysis (ESCA), and atomic force microscopy. It was found, from cell culture experiments, that NIH 3T3 cells on the PHBV/gelatin nanofibrous scaffold more proliferated than on the PHBV nanofibrous scaffold.