Subcritical crack growth in terms of velocity-stress intensity factor (v-K) curves in lead zirconate titanate (PZT) were experimentally characterized on poled and unpoled compact tension specimens. The poled specimens were tested under open- and short-circuit electrical boundary conditions, which resulted in an increase in fracture toughness by 0.2 MPa(.)m(1/2) for the accessible velocity range (v = 10(-9) to 10(-4) m/s) in the open-circuit case. Subcritical crack growth of unpoled specimens was obtained under ambient (relative humidity = 35%) and dry (relative humidity approximate to 0.02%) conditions over a regime in stress intensity factor of 0.5 MPa(.)m(1/2).