Nickel nanoparticles, to be used as catalysts for carbon nanotube (CNT) growth, were deposited on SiC fabric using four different methods vacuum impregnation, homogeneous precipitation, electrodeposition and autocatalytic plating. Results showed that suitable catalyst particles were produced by the vacuum impregnation process. The growth of CNTs was performed via a thermal chemical vapor deposition (CVD) process. A SiC/SiC composite was then fabricated by polymer impregnation and pyrolysis (PIP), by using the fiber fabric with insitu grown CNTs. The CNTs did not exert a marked influence on the density, porosity and thermal conductivity of the SiC/SiC composite. However, its mechanical properties were improved significantly, due to the weakening of the fiber-matrix interphase and the CNT reinforcement.