This paper describes a new efficient synthetic methodology to prepare Rh/phosphine functionalized carbon nanotubes and iron oxide magnetic nanoparticles via hydroaminomethylation reaction. These hybrid nanomaterials were fully characterized and evaluated in rhodium catalyzed styrene hydroformylation. The iron oxide magnetic nanoparticle based catalyst demonstrated high activity and selectivity for branched aldehydes, displaying easy recovery by magnetic separation without loss of activity in consecutive cycles.