Multivac is a family of fictional computers that are referred by Isaac Asimov in several of his science fiction stories; those stories can be grouped to form the Multivac series. The first appearances were in 1955, in the short stories Question and Franchise, but shows up in about twenty stories. As Asimov said in In Memory Yet Green, he was inspired by the UNIVAC I mainframe computer.

The specs vary among not only stories, but inside some stories themselves (as some have many generations of Multivacs). As an example, in The Last Question (1956), every generation of computers designs and builds its successor, and then transfers all its data.


Multivac computers began production in the 1990s, at the beginning of the robotic era following World War III.

During this time, the father of a boy called Roger worked with one. It began malfunctioning as it came up with different solutions each time to problems it was asked to solve. After coworkers told him to take a break, he took Roger out to lunch. His father told him what he thought was wrong with Multivac, and then from this Roger decided that it was like a child, and like one needed a break from work, saying that if you made a kid do work all day than it would get stuff wrong on purpose. His father reassured this inference with Roger, who confirmed it saying, "Dad, a kid's got to play too."

By 2008, Multivac was a key part of the United States’ electronic democracy, selecting a single person to answer a number of questions. Multivac would then use the answers and other data to determine what the results of an election would be, avoiding the need for an actual election to be held. Norman Muller of Bloomington, Indiana was the man chosen as "Voter of the Year" in the 2008 U.S. presidential election. Although the law required him to accept the dubious honor, he was not sure that he wanted the responsibility of representing the entire electorate, worrying that the result would be unfavorable and he would be blamed. However, after "voting", he was very proud that the citizens of the United States had, through him, "exercised once again their free, untrammeled franchise" – a statement that was somewhat ironic as the citizens did not actually get to vote; even he himself did not vote for any candidate, law, or issue.

On 21 May 2061, a week after Earth became a planetary civilization, and a bet with Alexander Adell, Bertram Lupov asked Multivac the question of how the threat to human existence posed by the heat death of the universe could be averted: "How can the net amount of entropy of the universe be massively decreased?" That was equivalent to asking, "Can the workings of the second law of thermodynamics be reversed?" Multivac's only response after much "thinking" was "INSUFFICIENT DATA FOR MEANINGFUL ANSWER."

By 3000, a new model was released: Microvac.