Overall, one of the key advantages of coupling biocatalysis with membrane technology is the ability to run biocatalytic reactions while simultaneously performing product/substrate separation from the enzymes, and from the reaction medium. Furthermore, it allows operating the synthesis process in continuous flow mode, which can enhance productivity and economic feasibility. Using multiple membranes in series with different molecular weight cut-offs (MWCO) can also enhance product selectivity, and the final step of membrane separation allows the concentration of the non-permeable product. The selected membrane material must be stable under the conditions (temperature, pH, presence of organic solvent) that optimize the enzyme's catalytic activity. When being coupled with membrane reactors, enzymes can be used either separately from the membrane devices, or as membraneimmobilized enzymatic reactors. This defines the two categories of hybrid processes that are discussed in this review. The coupling of enzymes with membrane reactors is exemplified in Section 2, while the use of membrane-immobilized enzymatic reactors is reviewed in details in Section 3.