A comparison has been made of thermoluminescence and thermally stimulated current in single crystals of calcium tungstate either doped with impurities or nominally pure but excited by ionizing radiation. Both effects were large in the case of monovalent impurities with glow peaks near 260 °K being characteristic of the impurity and peaks near 160 °K arising from an enhancement of a structure which normally results from radiation damage. Trivalent impurities had a lesser effect with the production of glow peaks near 300 °K. The structures responsible for the prominent glow peaks are suggested to be: 260 °K—monovalent ions in calcium sites, 154/160 °K—oxygen vacancies associated with either a W5+ or a monovalent ion at a calcium site, 300 °K—calcium vacancies. The occupancy of electron and hole traps is found to be related. This relationship is used to deduce information regarding the excitation mechanism for free holes and electrons in calcium tungstate.