Southern Brazil is an important foraging ground for several albatross and petrel species during breeding and non-breeding seasons. We present information on seabirds attending longline fishing vessels on Brazilian Exclusive Economic Zone and international waters of the Southwestern Atlantic Ocean (SW), based on 262 censuses. Spectacled Petrel (Procellaria conspicillata) was the most frequent and abundant species all around the year. Other species with significant numbers found in both warm and cold months were Yellow-nosed Albatross (Thalassarche chlororhynchos) and Great Shearwater (Puffinus gravis). Abundant species in winter were Black-browed Albatross (Thalassarche melanophris), White-chinned Petrel (Procellaria aequinoctialis), Cape Petrel (Daption capense), and Southern Fulmar (Fulmarus glacialoides). Seabird Bycatch per Unit Effort obtained during 32 cruises (351 sets and 371,368 hooks) was 0.09 birds/1000 hooks, and affected Black-browed Albatross (70.6% of birds caught), White-chinned Petrel, Yellow-nosed Albatross, and Spectacled Petrel. Strong overlap between longline fishery and seabirds in southern Brazil during winter is a major cause for concern.