Implementation of NPOAs requires in first place an assessment of all longline fisheries with presumption of occurring seabird incidental mortality. Chile took this responsibility in 2001 and started the NPOA-S process by estimating the seabird bycatch at the Patagonian toothfish fishery in southern Chile, a fishery and zone with high probabilities of having significant levels of incidental mortality. Final results of this study are presented now. Seabird bycatch rate during 2002 had a markedly temporal pattern, with very high values from September to December (0.37 to 1.28 birds/1,000 hooks). Main species caught was the black-browed albatross (96% of total birds). Considering the monthly fishing effort and bycatch rate, during 2002 a total estimated of 2,162 birds were incidentally killed. This result determined the initiation of the NPOA to reduce seabird incidental mortality in all longline fisheries in Chile, which is being developed during 2004 with the close collaboration of all industrial fishery companies. Despite this bycatch levels, black-browed albatross population at Gonzalo island, Diego Ramirez, seems to be increasing.