Absorption and photoluminescence spectra including the decay kinetics of the Pr3+-doped Lu2SiO5 were measured. Fast luminescence originating from the radiative 5d -> 4f transition of Pr3+ center is revealed with the maximum at 273 nm at room temperature. Low temperature photoluminescence decay is governed by the 25 ns decay, while substantial shortening to 6-7 ns occurs at room temperature. With the help of slow decay measurement in the millisecond time scale we evidence the thermal ionization of the relaxed excited 5d(1) state of Pr3+. The ionization can explain the observed temperature dependences of the decay times and emission intensity. (c) 2005 Elsevier B.V. All rights reserved.