The pandemic of COVID-19, which is caused by a positive-strand RNA virus SARS-CoV-2, has been continuing still in 2022. In July 2022, more than 560 million people have been infected with SARS-CoV-2 and more than 6 million people died of the virus-induced diseases. To date, more than 30 vaccines are approved and clinically used in the world to prevent SARS-CoV-2 infection and COVID-19 aggravation. Furthermore, some drugs have been developed and authorized including remdesivir, a repositioning inhibitor of RNA-dependent RNA polymerase from Ebola hemorrhagic fever, molnupiravir, a novel SARS-CoV-2 RdRp targeting inhibitor, and nirmatrelvir, an inhibitor of the main protease of SARS-CoV-2. We have also tried to develop antiviral agents against SARS-CoV-2 for increasing a repertory of drug choice. In the past three decades, we have been developing anti-HIV-1 agents including entry/fusion, protease, integrase and matrix/capsid inhibitors. According to the classification of viruses, HIV-1 and SARS-CoV-2 belong to positive-sense single-stranded RNA viruses and have some common characteristics. Therefore, we envisioned to apply our obtained knowledge and achievements in the researches on HIV/AIDS to the development of novel SARS-CoV-2 inhibitors. In this symposium I would like to introduce medicinal chemistry of antiviral agents against infectious diseases such as COVID-19 based on our strategy in development of anti-HIV agents.