Abstract: Piezoelectric relaxation and hysteresis in ferroelectric piezoelectric ceramics in the lead zirconate titanate system were studied in weak electric fields. The field and time dependences of the complex piezoelectric modulus were analyzed using a method and program for analyzing piezoelectric resonance spectra. A physical interpretation of the results obtained was proposed. © Pleiades Publishing, Ltd. 2024. ISSN 1062-8738, Bulletin of the Russian Academy of Sciences: Physics, 2024, Vol. 88, No. 5, pp. 709–714. Pleiades Publishing, Ltd., 2024.