In this chapter, it is clearly shown that modification of TiO2 with carbon gave positive effects. Among the most commonly employed modifications of TiO2 with carbon are doping TiO2 with carbon, coating TiO2 with carbon and also preparation of TiO2- carbon composite. These modifications have resulted in the improvement in its properties, which increased the catalytic activity. In particular, coating the surface of TiO2 with a layer of porous carbon increased the surface area and also the hydrophobicity of the TiO2. These improvements then led to the improvement of TiO2’s photocatalytic activity in oxidation reactions.