1-Hydroxy naphthyridine compounds (e.g., 1-hydroxy naphthyridin-2(1H)-one compounds of Formula I are inhibitors of HIV integrase and/or HIV RNase H and inhibitors of HIV replication: (I) wherein X and R1-R6 are as defined herein. The compounds are useful in the prophylaxis and treatment of infection by HIV and in the prophylaxis, delay in the onset, and treatment of AIDS. The compounds are employed against HIV infection and AIDS as compounds per se or in the form of pharmaceutically acceptable salts. The compounds and their salts can be employed as ingredients in pharmaceutical compositions, optionally in combination with other anti-HIV agents such as HIV antivirals, immunomodulators, antibiotics and vaccines.