Studies have been conducted on the enzymic activity of Baker’s yeast and also of Brewer’s yeast entrapped into the reversed micelles formed by cetyl pyridinium chloride (CPCl) in n-hexane. The activities of cc-amylase and invertase enzymes in the entrapped cells have been estimated and compared with those in the control experiments where there was no entrapment. The following significant observations have been made : 1. except for invertase, enzymes in Brewer’s yeast, the entrapped yeast cells showed enhanced enzymic activities; 2. when the yeast cells were entrapped inside the reversed micelles along with substrates of the two enzymes, ct-amylase, and invertase, the activity of each of these enzymes showed a further enhancement in comparison to that showed in the experiments in which substrates of the individual enzymes alone were entrapped - the phenomenon of synergism; 3. when the yeast cells and the respective substrates were entrapped inside separate reversed micelles and the solutions containing entrapped cells and entrapped substrates were mixed, the activities of the individual enzymes, a-amylase and invertase, showed further enhancement in comparison to the case in which the cells and the substrates were entrapped inside the same reversed micelle (in this ease also the phenomenon of synergism was observed); and (4) In the case of experiments in which there was no entrapment, it was observed that the presence of substrates induced more release of enzymes from the yeast cells. These observations on yeast cells, which to the best of our knowledge have not been reported before, should be biotechnologically relevant.