The excellent regio and steroselectivity of biocatalysts, combined with their environmental friendly behaviour, make possible to carry out under biocatalytical conditions many processes which, conducted on strictly classical methodologies, would demand expensive and tedious protection and de-protection steps. In this work we review some examples in which hydrolases (the most useful enzymes in the Biotransformations field) catalyse different reactions for synthesizing only the therapeutically essential stereoisomer of different homochiral building blocks for drugs. Thus, processes leading to antiviral, anticancer, antihypertensive or antiinflammatory drugs, along with many others, are described, remarking the versatility and utility of the biocatalysts in the above-mentioned processes