The use of fatty amines, obtained from natural fatty acids, in rubber compounds to improve silica dispersion was evaluated. Fatty amines can interact with the free silanol groups of the bis(3-triethoxysilyl-propyl) tetrasulfide (TESPT) silane-modified silica forming an amine-modified silica complex, which reduces the hydrophilic nature of the silica surface, minimizing the silica-silica interactions, and reducing the formation of secondary structures of silica. The effect of the addition of different amines and/or polyethylenglycol to SBR compounds loaded with silane-modified silica was evaluated. Finally, incorporation of fatty amines improved the processability and traction properties of rubber compounds loaded with modified silica. (c) 2006 Wiley Periodicals, Inc.