This paper presents results of an experimental study on heat transfer enhancement in nucleate pool boiling of a highly wetting liquid, pentane. on graphite fiber composite surfaces. Two kinds of composites are investigated : graphite-copper (Gr-Cu) consisting of graphite fibers in a copper matrix and graphite-aluminum (Gr-Al) consisting of graphite fibers in an aluminum matrix. Micro-graphite fibers of 8-10 mu m in diameter are embedded in the matrices with fibers being arranged perpendicular to the boiling surface. The highly wetting liquid has a nominal contact angle of between 2 and 4 degrees of most known surfaces. Pool boiling heat transfer performances of the graphite composites are compared with those of pure metal surfaces in the hysteresis region, which is commonly encountered within boiling startup periods, and the developed boiling region in which the overall performance is determined. It is revealed that the presence of graphite fibers reduces hysteresis effects in the startup region and also enhances overall performance in the developed region. In the hysteresis region, hysteresis temperatures are reduced more on the Gr-Al surface than on the Gr-Cu surface. In the developed boiling region, however; the heat transfer performance is enhanced more on the Gr-Cu surface than on the Gr-Al surface.