Dolphin-fish (Coryphaenahippurus) appear seasonally in Mallorcan waters from May-June to December, when the surface water temperature is higher than 16-18°C. Adult fish (63-117 cm fork length) are caught as a by-catch of the swordfish (Xiphiasgladius) fishery from spring to summer. Juvenile fish (14-70 cm fork length) are occasionally captured by purse-seiners, and are exploited by a traditional fishery, developed in the Island from late August to early December. Monthly progression of maturity stage and gonadosomatic index in adult fish showed are production period from June to September, in agreement with back-calculated birthdates determined from daily growth rings in the otoliths of juvenile fish. The back-calculated birthdates for adult fish showed a more protracted spawning period. Our results suggest a pre-spawning migration of C. hippurus intothe Mediterranean, following migratory patterns similar to bluefin tuna (Thunnusthynnus). The adult fish are probably originated from different spawnings, at least one occurring during the previous summer in Western Mediterranean waters, with a peak in June and July. This is the origin of the juvenile fishcaught by the traditional fisheries of the area between August and December (Malta, Tunisia, Sicily and Mallorca).