Use of microemulsion as a reaction media in the hydroformylation of different alkenes, namely styrene, cyclohexene and 1,2-diacetoxy- 2-butene have been studied using alkylpolygylcol ether- type nonionic surfactant in the presence of phosphine- modified rhodium catalyst. The combination of the experiments under comparable homogeneous and biphasic conditions were performed in order to make direct comparison of microemulsion with classical systems. Thus, the experiments were also carried out using catalysts such as unmodified rhodium carbonyl H Rh( CO) 4 and H Rh( CO)( PPh3)(3) in homogeneous system, Rh - TPPTS complex in two- phase system and in association with co- solvent.