Doping lead zirconate titanate (PZT) has often been examined in order to investigate changes in the electrical behavior of thin film ferroelectric capacitors.1In this study, PZT has been doped with Hf, Nb, and Zn. After reviewing the results of the initial studies, Zn doping of PZT was further investigated. Physical and electrical studies of Zn doped PZT have been conducted. These studies include x-ray diffraction analysis, hysteresis, pulsed switching, fatigue and retention measurements. Endurance measurements indicate an anomalous fatigue behavior of some Zn doped PZT thin film capacitors.