Abstract Abstract When an electric field is applied to a dielectric material under adiabatic conditions there is a resultant change in temperature, a phenomenon known as the electrocaloric effect. Compositions in the Pb(Zr,Sn,Ti)O3 system (PZST) have several phases of nearly equal free energy, allowing antiferroelectric (AFE) to ferroelectric (FE) and paraelectric (PE) to ferroelectric (FE) transitions to occur. Data are presented for electrocaloric measurements on AFE materials in the vicinity of the Curie point. The effect of microstructure is reported, and experimental values are related to dielectric properties through thermodynamic relations. Culmination of this work resulted in the largest electrocaloric effect (2.6°K) measured to date for coarse grain material in the PZST system.