Effects of heating rate on properties of stoichiometric Pb(Mg 1 / 3 Nb 2 / 3 )O 3 (PMN) perovskite ceramics produced by the reaction-sintering process are investigated. Without calcination, a mixture of PbO, Nb 2 O 5 and Mg(NO 3 ) 2 was pressed and heated to 1270 o C directly at various rates. Stoichiometric PMN ceramics of 100% perovskite phase are obtained at 5, 10, 20 and 30 o C/min heating rates. Density increases as heating rate increased from 5 to 10 o C/min and reaches a maximum 8.06 g/cm 3 at 10 o C/min. Grains 5.4-7.5 μm in size are obtained at heating rates from 5 to 30 o C/min. K m a x increases as the rate increases from 5 to 10 o C/min and decreases at higher rates.