The run-off was between favorite, novelist Mario Vargas Llosa leading a coalition of economically liberal parties collectively known as the Democratic Front and political underdog Alberto Fujimori of the populist and more moderate Cambio 90.

At the time of the 1990 elections the government of Alan García of the Peruvian Aprista Party (APRA) faced significant public disapproval.

Mario Vargas Llosa, a widely recognized writer, ran as the candidate of the tripartite coalition Democratic Front (FREDEMO).

Vargas Llosa was initially favored to win decisively, potentially eliminating the need for a runoff, particularly given the perceived weakness of the incumbent APRA party.

However, as the campaign progressed, Alberto Fujimori, representing the small new party Cambio 90, began to gain increasing support in the polls.

Vargas Llosa was supported by Ricardo Belmont, the newly elected mayor of Lima, and Ezequiel Ataucusi, the leader of the Agricultural People's Front.

Vargas Llosa also received backing from various media outlets and personalities, including the newspaper Expreso, Panamericana Televisión and television host Augusto Ferrando.