Feeding behavior of Antarctic krill (Euphausia superba) on salps was observed through onboard experiments during 1994/95 Kaiyo Maru Antarctic Ocean research cruise. Feeding rate was more than 1 salp/krill/day. Among 4 items of ethanol extracts; salps, phytoplankton, krill, and polychaets, krill preferred salps best. This evidence implies that the substances extracted from salps were most attractive to krill. The result of our experiment might indicate a tight ecological relationship between krill and salps. Since salps have ability to ingest wide size range of particles, there might also be a possibility of link between microbial loop and krill through salps.