The effect of the nature of alcohol, namely ethanol (EtOH), hydroxyethyl propionate (EPOH) and 2-hydroxypropyl propionate (PPOH), on the catalytic properties of Fe(acac)(3) and Cu(acac), is evaluated in the formation of mono- and diurethanes from hexamethylenediisocyanate (HDI). The highest turnover rate,77 h(-1), was observed with the reaction between HDI and PPOH catalysed by Fe(acac),, which also afforded a diurethane selectivity of 100%. Similar experiments conducted with a commercial catalyst, dibutyltin dilaurate (DBTDL), show that for the same reaction conditions, no diurethane adduct is formed and that the turnover rate is lower (19 h(-1)). A discussion concerning the probable active species is made in order to explain the activity, kinetic and selectivity results.