The kinetics of the hydroformylation of 1-octene by supported aqueous-phase catalysis, with water-soluble complex [Rh2(mu-(SBu)-Bu-t)(2)(CO)(2)(TPPTS)(2)], when the reaction occurs inside the pores of the silica support with particle size 60-200 mu m at mild conditions (0.5-1 MPa, 353-373 K) has been studied. The rate was found to be first order with respect to catalyst concentration and partial order with respect to partial pressure of hydrogen. The reaction was inhibited by high values of initial concentration of 1-octene and of partial pressure of carbon monoxide. During the reaction, no hydrogenation, no isomerization, nor oxidation products were observed. The selectivity in lineal aldehyde did not vary, neither during the course of reaction nor when varying the studied parameters in the tested range. Two different empirical kinetic models were tested. The best kinetic model showed a good agreement with the experimental data, with the average relative error of estimation less than 6.5%. The values of the activation energy (71 kJ/mol) as well as the values of the partial orders in CO, H-2, and octene were found to be similar to the values obtained previously for the hydroformylation of 1-octene at the external surface of the DS50 silica.