In this work, the regenerated silk protein with multiwalled carbon nanotubes (MWNT) was successfully electrospun in formic acid to generate the hybrid silk nanofibers. The morphology, structure and mechanical properties of the resulting silk/MWNT hybrid nanofibers were characterized using field emission scanning electron microscope (FE-SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FI-IR), Raman spectroscopy, wide angle X-ray diffraction (WAXD) and tensile testing. Thermo analysis was also carried out. TEM results confirmed that MWNT were well incorporated into the silk fibers. Addition of MWNT into silk nanofibers resulted in an enhanced mechanical property depending on MWNT content.