The distribution of members of the Anopheles farauti complex was studied in the Northern Territory of Australia during 3 surveys conducted in 1988, 1989, and 1990. At the time of these surveys An. farauti s.l. was common north of 15 degrees S along the coast and up to 50 km inland. The sibling species An. farauti 1, An. farauti 2, and An. farauti 3 were identified from 126 adult and larval collections using allozyme electrophoresis and species-specific DNA probes. Anopheles farauti 1 was the most abundant species along the coast and was found in 45% of collections. Anopheles farauti 2 had a more restricted range, occurring in 12% of collections on the east coast and in the central area of the survey region. Anopheles farauti 3 had the widest distribution of the 3 species, occurring on the coast and throughout the coastal plain up to 100 km inland. It was found in 43% of the collection sites. The distribution of the 3 sibling species is discussed with regard to the possibility of malaria transmission in the area.