A strategy for the immobilization of catalytically active transition metal complexes is described in which the rhodium hydride complex [(H)Rh(CO)(NaTPPTS)(3)] is electrostatically bound to highly charged polystyrene microspheres coated with cationic polyelectrolyte (see Figure). The catalytic activity of this latex-bound catalyst in the hydroformylation of methyl acrylate is reported and compared with its unbound equivalent.