Presidential elections were held in Chile on 4 September 1970. Salvador Allende of the Popular Unity alliance won a narrow plurality in the public vote, before having his victory confirmed by a Congressional vote after the Christian Democrats voted in favour of his candidacy.
Eduardo Frei Montalva and his Christian Democratic Party would later unite with Allende's opponents to form a congressional majority in an attempt to declare his presidency illegal in August 1973, catalyzing the Chilean coup of 1973 a few weeks later.
The election was held using the absolute majority system, under which a candidate had to receive over 50% of the popular vote to be elected. If no candidate received over 50% of the vote, both houses of the National Congress would come together to vote on the two candidates that received the most votes.