ABSTRACTRecombinant proteins are obtained using genetic engineering techniques and are widely used in various fields. Some recombinant proteins are difficult to express, purify, or are unstable or insoluble due to their structural characteristics. In order to address such issues, additional tags are fused at either the N‐ or C‐terminal end of the protein of interest during the cloning procedure. These tags range from a few residues to full‐length proteins or domains not only maintaining the structure of the natural protein but can be used to improve the solubility, stability, yield, or to confer new properties of the target protein. Here, the fusion tags commonly used in recombinant protein production and their functions are reviewed, and novel fusion tags are also summarized.