Amidations of abietic acid and rosin with isocyanates, a novel approach to modify rosin, were invest,igated using three isocyanates, namely cyclohexyl isocyanate, phenyl isocyanate, and tollyl isocyanate. The experimental results demonstrate that abietic acid and rosin reacted with the three isocyanates at 100 to 150 ℃ for 1 to 5 h to produce rosin amides in yields of 90 to 100%. The reaction temperatures were much lower than 200 to 300 ℃ at which conventional modifications of rosin are carried out. The amidation of abietic acid with phenyl isocyanate in toluene proceeded much faster than that in acetone or dioxane. The addition of triethylamine or N-methylpiperidine as a catalyst greatly accelerated the amidation rates of abietic acid and rosin with phenyl isocyanate. Molten rosin could react, with phenyl isocyanate without using a solvent, which can shorten synthetic route of rosin amides, and reduce reaction times. The rosin amides prepared under these conditions were in light color, and suffered from little oxidation and decarboxylation.