Eligible	Riga iz	Rio de Janeiro iz
From European zonal 1 (2)	Miles	Timman
From European zonal 2 (3)	Gruenfeld	Hübner, Kagan
From European zonal 3 (5)	Adorján, Ribli, Gheorghiu	Sax, Smejkal
From Soviet zonal (4)	Tseshkovsky, Kuzmin	Balashov, Vaganian
From US zonal (3)	Tarjan, Kavalek (did not arrive)	Shamkovich
From Canadian zonal (1)		Hebert
From Central American zonal 1 (1)		G.García
From Central American zonal 2 (1)	Hernández Onna (did not arrive)
From South American zonal (3)	Trois, Van Riemsdijk	Bronstein
From West Asian zonal (1)		Harandi
From Asian Pacific zonal (2)	Rodríguez	Torre
From Mediterranean-African zonal (4)	Ljubojević, Bouaziz	Velimirović, Ivkov
Seeded from 1977 candidates' matches (6)	Larsen, Polugaevsky, Hort (did not arrive)	Portisch, Mecking, Petrosian
Home player (2)	Tal	Sunye Neto
Replacements (2)	Mednis (replaced Kavalek), Romanishin (replaced Hort)