Agustín Mario Cejas (born 22 March 1945 in Buenos Aires) is a former Argentine football goalkeeper. He played for a number of clubs in Argentina and Brazil and has the all time record number of appearances for Racing Club de Avellaneda.
Cejas joined the Racing Club youth team in 1959 at the age of 13. He made his first team debut in 1962 at the age of 17. In 1966, he helped Racing Club to win the Argentine Primera. The following year Racing won the Copa Libertadores 1967 to become Libertadores champions of South America for the only time in the clubs history. They followed this up by beating Celtic F.C. in the Copa Intercontinental to become the first Argentine club champions of the world.
In 1970, Cejas joined Santos in Brazil where he played in the same team as Pelé. In 1973, Cejas helped Santos to win the Campeonato Paulista and received the prestigious Bola de Ouro as the best player in Brazil.
Cejas returned to Argentina in 1975 for a brief spell with Club Atlético Huracán before going back to Brazil to join Grêmio.
In 1977, Cejas returned to Racing Club where he played until 1980. By the end of his second period with the club he had set a club record of 313 appearances. He then had a short spell with River Plate where he was part of the squad that won the Nacional in 1981.
Cejas played for Argentina at the 1964 Summer Olympics.