Morphological characteristics of nymphal instars are described for a Korean wood-feeding cockroach, Cryptocercus kyebangensis. Eleven instars, including adults, were tentatively identified. Female adults had apicolateral emargination and a truncated apical median prominence in the seventh sternite, and female nymphs of the other instars except for the last had a narrowly rounded apical median prominence in the seventh sternite. In the last instar, the seventh sternite was partially desclerotized and somewhat shriveled at the start of the emarginated area. In contrast, males showed no emargination in adults, and had a rounded broad apical median in this area of all instars. In the ninth sternite, female nymphs had a medium notch on the caudal margin and styli were separated before reaching adulthood, whereas no such notch was observed in male nymphs. The styli remained prominent in the ninth sternite of male adults.