A two-step chemoenzymatic synthesis of urethane oil, consisting of a lipase-catalyzed transesterification of castor oil with n-butanol and a reaction of the resulting precursor (partial esters) with different diisocyanates, was studied. The effect of the type of lipase, alcohol chain length, solvent, and temperature in the transesterification step was examined. Urethane oils were characterized by IR, H-1-NMR, and GPC techniques. The film properties were also tested. The composition varies with time in the transesterification step. Conversions were faster and more complete using lipozyme, where yields to 75% could be achieved. Enzyme activity increases with increase in the log P value of the solvent. The degree of transesterification and composition of the precursor have influence on the molecular weight and film properties of urethane oils. A good correlation was observed between the scratch resistance and monoglyceride percentage of the precursor of the respective urethane oils,