The dielectric frequency relaxation and average phase transition temperatures, T-m, of some PZN-PT-BT ceramics have shown unusually large variation by annealing method. T-m becomes higher and the relaxation is weaker with annealing. The experimental behaviors can be understood using a model of BZN nano-phase regions embedded in the PZN-PT-BT solid solutions. (C) 2002 Elsevier Science B.V. All fights reserved.