Abstract : Various spinning trials of polyacrylonitrile (PAN) and PAN/carbon nanotube (CNT) fibers were conducted using single- and bi-component spinning to obtain precursor fiber for carbonization. Materials parameters, such as homo- vs co-polymer, as well as different molecular weight polymers were investigated. In order to obtain better precursor fiber with circular cross-sectional shape, gelation bath composition and bath temperature were varied in the spinning process. The precursor fiber containing 0.5 to 1 wt% CNT exhibited tensile strength in the range of 0.6 to 1 GPa and tensile modulus in the range of 16 to 28 GPa. The PAN/CNT precursor fibers were subsequently stabilized and carbonized in the batch process by varying stabilization conditions such as tension, temperature, and residence time. The effective carbon fiber diameter from core precursor fiber was in the range of 3.5 - 4 microns. The highest average tensile strength and modulus were 5.5 GPa and 362 GPa while the maximum properties for the individual filaments were up to 6.8 GPa and 389 GPa, respectively. This study proves that PAN/CNT technology can be used to process carbon fibers with a tensile strength approaching 7 GPa and tensile modulus approaching 400 GPa at a relatively low carbonization temperature of 1300 degree C.