The Bolivian National Congress 1966–1969 was elected on 3 July 1966.
Electoral alliance formed by Popular Christian Movement, MPC; Social Democratic Party, PSD; Revolutionary Left Party, PIR; Authentic Revolutionary Party, PRA.
CDC – Christian Democratic Community (Comunidad Democratica Cristiana).
Electoral alliance formed by Bolivian Socialist Falange, FSB; National Association of Democratic Professions, ANPD; Democratic Revolutionary Alliance, ADR.
MNR-Paz – Revolutionary Nationalist Movement-Víctor Paz Estenssoro.