From a combined study of the electrical properties between room temperature and 77 K and optical absorption at 300 K of bulk CuInSe2 samples doped with different oxygen concentrations, two shallow acceptor levels are found. The activation energy EA1 and EA2 of these levels in the dilute limit tends to be around 30 and 36 meV, respectively. The increase of EA1 and decrease of EA2 with the increase of oxygen content can be explained consistently on the basis that the ratio of Cu to In atoms increases with the increase of oxygen incorporated into CuInSe2 lattice.