The electrical fatigue of sol-gel derived ferroelectric lead zirconate titanate (PZT 50/50) and antiferroelectric lead zirconate (PZ) thin films was found to strongly depend on the orientation and morphology, Compared to the PZT films, the PZ thin films showed a much slower degradation of polarization, due to their having less internal stress during 180 degrees domain switching of the antiferroelectric phase. More than 70% of the initial polarization Value of PZ thin films was maintained after 10(9) cycles of 15 V bipolar square pulse. The randomly oriented PZT films showed less degradation of polarization, compared to the (111) preferred PZT films. In the PZ thin films, the rosette structure with a large portion of pyrochlore phase caused severe fatigue because of nonuniform distribution of electric field and internal stress.