Both XPS core level and valence band spectra were obtained from an E-120 high modulus pitch-based carbon fiber surface. The XPS data show that the E-120 fiber had the least oxygen content on the surface compared to various other pitch-based (e.g., E-35, E-75,P-55X, etc.) and PAN based carbon fibers (e.g., AU4, TypeII, etc.). [See Y. Xie and P. M. A. Sherwood, Appl. Spectrosc.43, 1153 (1989); Chem. Mater.1, 427 (1989);2, 293 (1990); Appl. Spectrosc.44, 797 (1990); Chem. Mater.3, 164 (1991); Appl. Spectrosc.44, 1621 (1990);45, 1158 (1991); Y. Xie, T. Wang, O. Franklin, and P. M. A. Sherwood,ibid.46, 645 (1992).] E-120 also had the most graphitic structure in both the surface and the bulk among these fiber samples as evidenced by both XPS and XRD. No nitrogen was found on E-120 and other pitch-based carbon fiber surfaces but it was found on PAN-based fibers. Our previously reported work [Y. Xie and P. M. A. Sherwood, Chem. Mater.1, 427 (1989);2, 293 (1990); Appl. Spectrosc.44, 797 (1990); Chem. Mater.3, 164 (1991); Appl. Spectrosc.44, 1621 (1990);45, 1158 (1991); Y. Xie, T. Wang, O. Franklin, and P. M. A. Sherwood,ibid.46, 645 (1992)], showed that XPS valence band spectra were more sensitive to chemical environment on the fiber surface than core level spectra and could well be interpreted by X–αcalculations with model components.