Orange phosphorescence from Eu3+-activated CaO and SrO and violet phosphorescence from Pb2+-activated SrO were clearly observed after the materials had been excited with ultraviolet light. The orange phosphorescence resulted from D-5(0) to F-7(1) transitions of the Eu3+ ions and the violet from P-3(0) to S-1(0) transitions of the Pb2+ ions. The phosphorescence lasted >1 h. Trapped-electron centers and hole centers Introduced into the CaO and SrO hosts by the ultraviolet light appear to have been responsible for generating the long-lasting phosphorescence.