Infectious diseases remain as a major world health problem due to the rapid development of resistance to the existing antimicrobial drugs. The spread of resistance among Gram-positive and Gram-negative bacteria as well as fungal pathogens, correlated with increasing limitation in the availability of therapeutic options represent a growing challenge for the development of new antimicrobials. The purpose of this book is to present an updated perspective upon the use of thiourea derivatives as antimicrobial agents, as well as the combination with nanoparticles for enhancing their antimicrobial efficacy, in order to highlight potential new solutions to cope with infections resulting from drug-resistant and biofilm forming microorganisms. The thiourea derivatives could represent novel and promising antimicrobials, which target not only the actively growing microorganisms, but also the non-multiplying, biofilm embedded microbial cells. Moreover, using novel core/shell/adsorption-shell to inhibit the microbial adherence could be of a great interest for the biomedical field, opening new directions for the design of film-coated surfaces with improved anti-biofilm properties.