Morphological development of the larvae and juveniles of the rockfish, Sebastes minor, was investigated using specimens (4.75-18.18mm SL) collected from the northern Japan Sea, in 1986-1988. Notochord flexion had already begun in the smallest larva (4.75mm SL) collected, and was completed in those of about 6mm SL. Transformation to pelagic juveniles occurred between 8 and 12mm SL. Both larvae and juveniles exhibited a species-specific melanophore pattern on the body. Other morphological features particularly the development of head spines, are also described. In August-September, the larvae and pelagic juveniles of S. minor occurred in coastal waters off Hokkaido and Primorskaya, and in offshore waters in the northern Japan Sea, north of the subarctic convergence. In this season, S. minor was the most dominant of the pelagic fish larvae throughout offshore regions of the northern Japan Sea. Gut contents analysis of S. minor showed calanoid copepodids (mainly Paracalanus sp.) to be the major dietary component in both the larvae and pelagic juveniles.