A screening of six different immobilized lipases (C. rugosa, C. antartica, P fluorescens, M. miehie, R. niveus) was done to determinate the best for the stereospecific hydrolysis of RS-O-BP. An experimental design (23) where the enzymatic activity was a function of temperature, buffer concentration and solvent was selected. P fluores-cens showed the best results for S(-) isomer, with an increase of the stereoespecificity ratio of 1.5, using tetrahydrofuran as solvent, and 15mM buffer phosphate concentration at 37 oC. C. rugosa show-ed the best results for R(+) isomer, with an increase of the stereoespecificity ratio of 1.7, using acetone as solvent, and 25 mM buffer phosphate concentra-tion at 15 oC. The enantiomeric excess of S(-) propranolol with P fluorescens was 87%, higher than those reported elsewhere.