Nanostructured ceramics of α-Al 2O 3 was prepared by means of high temperature vacuum sintering of high purity alumina powder. Scanning electron microscopy showed that after sintering particles size expanded slightly but did not exceed 300 nm. The main features of thermal and pulsed cathodoluminescence of nanoceramics were studied. It was revealed that luminescence bands are produced by oxygen vacancies in anion-defective α-Al 2O 3 single crystals. It was found that Cr 3+ ions contribute to luminescence intensity in spite of their extremely low concentration as well.