A novel rhodium-based catalyst was developed for homogeneous hydroformylation in supercritical carbon dioxide. The catalyst, trans-RhCl(CO)(P(p-CF3C6H4)(3))(2), has in the supercritical fluid reaction mixture moderate solubility (>5.5 mM), 2 orders of magnitude greater than most conventional metal-triphenylphosphine catalysts. Homogeneous catalytic hydroformylation of 1-octene using the novel catalyst was carried out at 343 K and 272 atm. Conversion of 1-octene was complete, with a normal/branched aldehyde ratio of ca. 2.4 and negligible hydrogenation or isomerization products. The catalyst was also recoverable in its original form, as confirmed by P-31 NMR and FTIR spectroscopy.