Surface carbonates on BaTiO3 (BT) ceramic powders were characterized by diffuse reflectance infrared Fourier transforms (DRIFT) spectroscopy and total carbon analysis (TCA) techniques. Three lots of as-received BT powders were calcined at various temperatures and atmospheres, and aged at room temperature in ambient atmosphere. It was evident from DRIFT spectroscopy and TCA results that all BT powders were different in the amount of carbonates and in the susceptibility to carbonation in air. The carbonates on BT surface decompose after firing at temperatures above 600 degreesC. At 1000 degreesC, the removal of carbonate was shown to be a function of the partial pressure of CO2 in the calcination atmosphere. When the calcined BT was aged in ambient atmosphere, the carbonation easily reoccurred.