Kinetic experiments of the oligomerization reaction were carried out in a spinning basket reactor, suitable for gas-liquid-solid systems. The catalyst used is an amorphous mesoporous silica-alumina (MSA) showing outstanding catalytic activity in the propylene oligomerization [G. Bellussi, C. Perego, A. Carati, S. Peratello, E. Previde Massara and G. Perego, Proceedings of the 10th International Zeolite Conference, Garmisch-Partenkirchen, Germany, 17-22 July 1994, Stud. Surf. Sci. Catal. 84 (1994) 85.]. The reaction rate of oligomerization, catalyzed by MSA extrudates [G. Bellussi, C. Perego and S. Peratello, US Patent 53 428 14, 1993.], has been described by a Langmuir-Hinshelwood-Hougen-Watson kinetic model and by considering the fugacity of reactants involved. The estimated activation energy (similar to 18 000 J/mol) together with the experimental results suggest that the propylene oligomerization is limited by mass transfer inside the mesopores of MSA phase.