A study has been made of the kinetics of the hydroformylation of 1-dodecene in the presence of a rhodium catalyst with a polymer phosphine ligand. Benzene was used as the solvent. The differences in the kinetic relationships from triphenylphosphine when a polymer ligand is used are attributed to the fact that in solution the macromolecules of the polymer ligand are in the form of coils in which the concentrations of phosphine groups is much higher. The main relationships governing catalysis by carbonylphosphine systems can be explained on the basis of the assumption that, with high contents of phosphine groups (polymeric phosphine, high concentrations of triphenylphosphine) the reaction rate is limited by reaction of the olefin with the catalyst HRh(CO)P2. If there are few phosphine groups, reaction with a different form of catalyst HRh(CO)2P occurs rapidly and limits the process of hydrogenolysis of acylrhodiumcarbonyl complexes.