The optical absorption coefficient of Ti:Al2O3samples at 490 nm for the &pgr; polarization (E∥cˆ) is found to be proportional to the concentration of Ti3+ions, as determined by measurement of the paramagnetic moment as a function of temperature and magnetic field. The experimental data yield the value &sgr;=(9.3±1.0)×10−20cm2for the absorption cross section of Ti3+, the active ion in the tunable Ti:Al2O3laser, at the peak of the laser pump band.