Addition of cyclodextrin in the biotransformation of digitoxin into digoxin by Digitalis lanata cell suspension cultures enhanced the conversion yield. Presence of cyclodextrin also supported good stability of the intermediate product, digoxin, for long time. Among several kinds of cyclodextrins, ${eta}$-cyclodextrin provided the best results. It was found that the optimum form of cyclodextrin utilization was the external addition of iclusion complexes between digitoxin and ${eta}$-cyclodextrin at 1: 2 molar ratio from the beginning of biotransformation. With the optimized conditions, addition of ${eta}$-cyclodextrin enhanced the production of digoxin up to 1.55 fold. In this case, not only digitoxin consumption was increased, but also the production of by-product was reduced.