The invention relates to a method for the hydroformylation of olefins with at least 7 carbon atoms. According to said method a) the olefin is subjected to a hydroformylation reaction together with carbon monoxide and hydrogen in the presence of a complex consisting of rhodium and a polymeric complex ligand with more than 10 nitrogen atoms and having a molar mass greater than 1000 g/ mol, as well as a solubilizing agent, at a temperature of between 40 and 200 DEG C and a pressure of between 1 and 600 bar in a reaction zone, such that in these reaction conditions the solubilizing agent together with the olefin and the resulting hydroformylation product forms a largely uniform phase in which the complex is solubilized; b) in said reaction mixture a phase separation into a phase rich in solubilizing agent and a phase poor in solubilizing agent is induced, the complex preferably being present in the phase rich in solubilizing agent and the hydroformylation product preferably present in the phase poor in solubilizing agent; and c) the above phases are separated. Phase separation is preferably induced by cooling or by addition of a phase-separating agent such as water.