Fed-batch fermentations were carried out in order to improve the efficiency of hirudin production by recombinant Saccharomyces cerevisiae. A fed-batch fermentation done with the optimized semi-synthetic medium resulted in a maximum hirudin concentration of 342mg/$ell$ by keeping a galactose concentrations between 10 and 30g/$ell$ which corresponded to a 11.4-fold increase in hirudin concentration compared with the simple bach fermentation done with the same medium. Comparison of the chromatographic pattern of proteins in the growth medium clearly showed that the use of the semi-synthetic medium is more advantageous for separation of hirudin than the case o fusing the complex medium. Continuous cell recycle fermentation done at dilution rate of 0.1h-1 and an inlet galactose concentration of 100g/$ell$ yielded a maximum hirudin productivity of 19.1mg hirudin/$ell$$.$h.