The objective of the research was to assess the effect of carbon chain length of carboxylic acids and of the immobilization process of yeast (running in the calcium alginate or in poly(vinyl alcohol) on the rate and yield of the hydrolysis reaction of phenyl esters. The course of this reaction was monitored using a gas chromatography method with a BPX 70 capillary column and a flame ionization detector applied. It was found that the catalytic effect of the Saccharomyces cerevisiae baker`s yeast decreased with the increasing l carbon chain length of carboxylic acids. Although the immobilization of yeast caused a slight drop in the rate of hydrolysis, however, it also facilitated the isolation of product and made it possible to multiply use the biocatalyst.