Disinfection of microbial aerosols gained significant attention among researchers worldwide due to increasing flu pandemics and bioterrorism threats. Ultraviolet germicidal irradiation, HEPA filtration, and photocatalytic oxidation are conventional methods of bioaerosol inactivation, and new approaches developed in recent years include application of cold plasma and plasmacluster ions, microwave irradiation, ion emission, thermal treatment, applications of nanoparticles and nanotubes in filtration media, and application of natural products in filtration media. Although all these methods have shown promising responses for airborne microbial inactivation, they have some inevitable limitations. Most of the methods were tested in the laboratories, and adequate field data are still lacking. Furthermore, most of these methods were never tested for real pathogens and emerging drug-resistant pathogens. Advantages and disadvantages of all these conventional and newly developed approaches have been discussed in this review article. The authors conclude that a perfect solution to inactivate all airborne microorganisms does not exist yet. We can combine different microbial inactivation methods to achieve a more effective disinfection approach depending on the types of suspected microorganisms and indoor environmental conditions.