Sr0.33Ba0.67Nb2O6:Cr (0.02 mol%) single crystals have been prepared by the Czochralski method. They were investigated by electron paramagnetic resonance and photoluminescence in a temperature range of 3-300 K. The FPR signal shows at least two magnetically non-equivalent centers. We have calculated temperature and angular dependences of the EPR spectra, and spin Hamiltonian parameters for both centers. Low temperature photoluminescence spectra reveal emission bands at 765 and 824 nrn in addition to an intense emission band at 537 Rm. From the EPR and PL analysis, it is suggested that two different Cr-associated defect centers are present in this crystal. (C) 2014 Elsevier B.V. All rights reserved.