Thermal expansion properties have been measured for the ceramic lead zirconate titanate-lead zinc niobate [(1 - )PZT-()PZN] in the temperature range of -100 to +450 A degrees C. For all ceramics examined, the deviations from the straight line below Burns temperature were observed. The dynamic polarization fluctuations in their relaxor compositions are believed to play a role in this deviation. Burns temperature was determined and the local polarization ( (d)) was calculated from the thermal expansion data. Various aspects of understanding the polarization behavior and other effects in this ferroelectric system were examined and discussed.