Distribution, reproduction, and diet of the gray reef shark Carcharhinos arnblj. rhynchos were investigated using data collected during shark control programs in the main Hawdiian Islands (MHI) and during research fishing in the Northwestern Hawaiian Islands (NWHI). A total of 472 sharks were caught between 1967 and 1980. These sharks have a restricted distribution in the MHI; they were collected only in the vicinity of Niihau and Molokini islands, but were one of the most abundant sharks throughout the NWHl. Catch rate was higher for males than for females in standard longline fishing at all locations and dunng all seasons. Most shdrks were caught at depths between 20 and 60 m, and depth distribution of the sexes was similar, although females were more common at shallower depths. hlales ranged in size from 79 to 185 cm total length (TL), and matured at between 120 and 140 cm TL. Females ranged in size between 63 and 190 cm TL and matured at about 125 cm TL. Litter size ranged from 3 to 6, with an average of 4.1 pups. Size at birth was estimated to be just over 60 cm TL. Most sharks (85%) consumed teleosts, but some fed on cephalopods (29.5'%), and crustaceans (4.9%). For sharks in the largest size classes, the frequency of occurrence of teleosts declined, whereas that of cephalopods~ ncreased.