Hydrothermal and commercial barium titanate powders were examined for undesirable impurity phases. Compositional differences in the powder were evaluated using x-ray diffraction (XRD), x-ray fluorescence (XRF), and x-ray photoelectron spectroscopy (XPS). A barium-rich impurity phase, virtually undetectable by XRD, was detected via XPS. Barium impurity phase peaks were detected at binding energies @1.5 eV higher than those characteristic of barium in a barium titanate bonding state for both the Ba 3d and Ba 4d transitions. Simple curve-fitting techniques were used to quantify the percentage of barium in a barium titanate bonding state versus another barium bonding state for each set of doublets. The barium impurity bonding state accounted for 20-50 mol% of the barium detected by XPS.