Human viral pathogens are a serious cause of illness worldwide, and are responsible for a significant number of infectious diseases. Recurring respiratory infections account for the greater part of the disease burden associated with viral infections in infants, while we see more and more emerging viruses affecting this population, especially in Asia. Human respiratory syncytial virus (hRSV) and Human parainhuman fluenza type-3 virus (hPIV-3) are the main aetiological agents of acute lower respiratory tract infection in in- fants worldwide. Analogously, enterovirus 71 (EV71) is a major cause of hand foot and mouth disease (HFMD) in Asia, an ordinarily benign paediatric disease that in some cases develops to a severe neurological infection. Sadly, neither vaccines nor drugs are to date available to prevent or treat infection by either of these viruses. The work presented in this Thesis is focussed on the discovery of novel inhibitors of hPIV-3, hRSV and EV71 infection, by using multidisciplinary approaches and various drug discovery strategies.