See main article: 1985 Buenos Aires Grand Prix (tennis).
Martín Jaite defeated Diego Pérez 6–4, 6–2 to win the 1985 Buenos Aires Grand Prix singles competition. Guillermo Vilas was the champion but did not defend his title.
Alejandro Ganzábal (first round) Martín Jaite (champion) Horacio de la Peña (semifinals)
Jimmy Brown (semifinals) Eduardo Bengoechea (first round) Roberto Argüello (quarterfinals)