The effect of persistent photoconductivity (PPC) and their associated deep centers have been studied for Zn1-xCdxSe (0.10 < x < 0.26) alloys grown by molecular beam epitaxy on GaAs substrates. Low temperature photoexcitation showed a prominent PPC effect with an exponential temperature dependence of the characteristic of the carrier decay time and an energy barrier which changes with Cd concentration. Experiments of thermally stimulated currents indicated that the PPC effect may be associated to deep electron traps levels whose activation energies are a function of the Cd concentration. (C) 2002 Published by Elsevier Science Ltd.