We present the results for the reproductive biology of Patagonian toothfish (Dissostichus eleginoides) caught off southern Chile from January to March and June to November 2006. A total of 10,896 specimens were measured (55-220 cm total length, TL) and sexed (7,049 males, 64.7%; and 3,847 females, 35.3%). Macroscopic observations showed that gonad maturation begins at 60 cm TL in both sexes, with an average maturation size of 81 cm TL in males and 89 cm TL in females. This species appears to have an ampie spawning period that occurs only off the far southern region of Chile. To date, no evidence indicates that this resource reproduces in any other areas of the Pacific Ocean off the coasts of South América, where no specimens were observed with mature gonads, percentages of atresia were high, and juvenile fish were not caught in trawl fishing operations targeting other commercial species.