Hydrophobin, a functional protein produced by filamentous fungi, is a kind of bio-surfactant with no catalytic function. It is self-assembled without auxiliary additives to form various hydrophobic-hydrophilic interfaces. The unique chemical and biological properties of hydrophobin provide the possibilities to create versatile biomaterial for specific applications through protein engineering and combinatorial approaches. In particular, it is known to avoid immune reactions and thus can be used in a wide range of bio-compatible and medical application areas including an emulsification and surface modification, a protein purification tag, a cell immobilization tool, an antibacterial coating agent and a biosensor. However, hydrophobins secreted from wild-type organisms (typically filamentous fungi, ascomycetes and basidiomycetes) have some hurdles to apply for commercial use because of low productivity and difficult to scale up. This review examines the up-to-date reports on the structural characteristics, production and application examples of recombinant hydrophobins.