Baicalein and baicalin are flavonoid compounds isolated from medicinal herb Scutellaria baicalensis Georgi (Labiatae) and have been known to possess antiviral activities. In the present study, we investigated the in vitro effects of baicalein and baicalin on the three distinctive enzymatic activities of the human immunodeficiency virus type-1 (HIV-1) integrase-endonucleolytic, integration, and disintegration activities. Both compounds inhibited the three enzymatic activities in a dose-dependent manner. The 50％ inhibitory concentrations of baicalein and baicalin for endonucleolytic activities of HIV-1 integrase were 4.4$pm$3.3 and 25.9$pm$4.0$mu$M, respectively. In general, baicalein exhibited nearly 6- to 10-fold stronger inhibition than baicalin for the three enzymatic activities. These data demonstrate that baicalein or baicalin can be used as a leading compound to develop anti-AIDS chemotherapeutic agents targeting to the HIV-1 integrase.