We report a method using SEM, EDX, SIMS, and polarization-voltage hysteresis data to investigate changes that occur in PZT thin films fatigued using low (below 100 kHz) frequency square waves. Fatigue in PZT capacitors can limit the lifetime of destructive readout ferroelectric memories. Identification of physical and electronic changes that occur during fatigue will lead to understanding fatigue mechanisms and the development of improved electrode-ferroelectric interfaces.