Due to the vastness of the science virology, it is no longer an offshoot solely of the microbiology . Viruses have become as the causative agents of major epidemics throughout history . Many therapeutic strategies have been used for these microorganisms, and in this way the recognizing of potential targets of viruses is of particular importance for success . For decades, antibodies and antibody fragments have occupied a significant body of the treatment approaches against infectious diseases . Because of their high affinity, they can be designed and engineered against a variety of purposes, mainly since antibody fragments such as scFv, nanobody, diabody, and bispecific antibody have emerged owing to their small size and interesting properties . In this review, we have discussed the antibody discovery and molecular and biological design of antibody fragments as inspiring therapeutic and diagnostic agents against viral targets.