Using a tunable semiconductor laser in the spectral range of 380cm-1 to 500cm-1, laser-induced photoconductivity spectrum from shallow acceptor impurities in silicon was observed for the first time. The photon flux on the sample was typically 1018 per cm2-sec., and the photon energy was smaller than the ionization energy of the impurities. Two photon transition is suggested for the representation of the spectrum. Resonances in the photoconductivity spectrum are observed for the photon energies corresponding to the 2p1 and 2p2 states of Si:Al which act aa intermediate states for the two photon transition. Anti-resonanoe due to two photon transparency is also observed.