Heterogenization of HRh(CO)(PPh3)(3) tethered through phosphotungstic acid to zeolite Y support, gives a novel hydroformylation catalyst with excellent stability, reusability and even improved activity. The activity, selectivity and stability of this catalyst for hydroformylation ofa variety of linear and branched olefinic substrates have been demonstrated. The heterogenized HRh(CO)(PPh3)(3) catalyst was recycled several times without loss of any activity. The catalyst was characterized by powder XRD, SEM, XPS, and P-31 CP MAS NMR to establish true heterogeneity and morphological characteristics. (C) 2003 Elsevier Science (USA). All rights reserved.