Coronaviruses (CoVs) infect humans and can cause lung, kidney, heart, brain, and intestinal infections that can range from mild to lethal type. Especially, β-coronaviruses causing severe-acute respiratory syndrome (SARS)-CoV-1, the Middle East respiratory syndrome (MERS)-CoV, and SARS-CoV-2 (2019-nCoV) are dangerous and can easily be transmitted from human to human. The outbreak of coronavirus disease 2019 (COVID-19), which is caused by SARS-CoV-2 infection, has become a global crisis. In this situation, the development of anticoronaviral therapies is highly warranted. However, to date, no approved vaccines or drugs against CoV infections are available. In this chapter, we have made an effort to discuss molecular level targets for the development of therapies against coronavirus diseases, SARS-CoV-1, MERS-CoV, and SARS-CoV-2, targeting CoV replication and its life cycle. These targets include the spike glycoprotein and its host-receptors for viral entry, proteases that are essential for cleaving polyproteins to produce functional proteins, and RNA-dependent RNA polymerase for viral RNA replication.