Two research cruises, one in the northwestern waters off the Hawaiian Archipelago between Oahu and Midway Islands in April-May 1989, and another along 26°N and 29°N between Ogasawara and Midway Islands in April-May 1993, were organized to investigate the spatial distribution of spawning grounds for the commercially important flying squid. Ommastrephes bartrami. Presence of rhynchoteuthion paralarvae and the distribution of mature females suggest that the spawning grounds of O. bartrami in April-May lie in the area extending from the waters off Ogasawara Islands to the Hawaiian Archipelago.