How many men have served as US vice president?

Through Joseph Biden (January 20, 2009), there have been 47 men who served as Vice President of the US, all but two of them elected to the position. The first 3 Vice Presidents were actually "runners-up" for President, until the 12th Amendment was ratified in 1804.

Two Vice Presidents, George Clinton and John C. Calhoun, served under 2 presidents, but several Presidents had more than 1 Vice President. Four Vice Presidents who succeeded to the office had no Vice President of their own (Tyler, Fillmore, Andrew Johnson, and Arthur).

Both Gerald Ford and Nelson Rockfeller were appointed under the terms of the 25th Amendment.