An adaptive optics system was developed for the 8.2-m Subaru Telescope operated by the National Astronomical Observatory of Japan on the summit of Mauna Kea in Hawaii. The system saw first light on 2 December 2000 and achieved diffraction limited imaging in the K- and L- band. The system is located at the Cassegrain focus of Subaru and can feed either IRCS, an infrared camera and spectrograph (used for first light) or CIAO, an infrared coronagraphic imager. The system features a 36-elements curvature sensor using avalanche photo diodes and a 36-electrodes bimorph deformable mirror. The curvature sensor and deformable mirror were custom designed for an optimum match. Wavefront sensing is performed in the visible range while AO-corrected observations are made in the infrared. In this paper the first AO observations are described and the system performances are compared with the design values. A comparison is also made with other existing AO systems. First scientific demonstrations are shown.