Striped bonito Sarda orientalis larvae and juveniles were reared in a laboratory from hatching to 14 days post hatching, and the development of their digestive system was investigated histologically. On day 2 (first feeding day),the larval-type digestive system was, differentiated. On day 3, a blind sac with densely distributed gastric glands developed and pyloric ceca appeared, suggesting that the digestive system was attaining adult-type structure. The yolk was completely absorbed on day 4. Bonito. larvae preyed on rotifers and/or Artemia nauplii on day 2, but almost the whole. gut, was occupied by fish larvae. from,day 4. In the striped bonito, the adult-type digestive system was established right after first feeding, and this precocious development was well synchronized with, the appearance. of piscivory.