The effects of the presence of water on the rhodium-catalyzed carbonylation of isopropylallylamine were studied as a function of the following parameters: reaction temperature; water content; presence of phosphines; solvent polarity and presence of bulky ions. It turned out that the reaction is strongly dependent on the temperature and that water seems to behave both as a source of hydrogen and as a ligand in the active species. The phosphine ligands showed no effect since in the presence of water they were all converted to their corresponding oxides.