As of February 2017, how many men have served as Vice President of the United States?

There have been 48 US Vice Presidents.

Initially, the Vice President was the candidate that received the second most number of Electoral Votes, but that was changed soon after Jefferson and Burr were tied in 1800.

While Adams and Jefferson were both elected President while still Vice President, Martin Van Buren and George HW Bush are the only subsequent sitting VPs to be elected President since then. Richard Nixon is the only VP to be elected President while not in office.

Eight VPs have become President due to the death or assassination of the President, but only three of them, Teddy Roosevelt, Harry Truman and Lyndon Johnson were subsequently re-elected President.

Seven VPs have died in office and two resigned the office, John Calhoun to become a US Senator and Spiro Agnew, as a condition of a plea bargain related to bribes and tax evasion while in office in Maryland.

Until the ratification of the 25th Amendment on February 10, 1967, there was no mechanism to replace the vacated Vice Presidency until the next election. Gerald Ford, and his eventual VP, Nelson Rockefeller are the only two men to be appointed Vice President due to its vacancy. The amendment also allowed for VPs Bush and Cheney to serve as "acting Presidents" due to surgeries on Presidents Reagan and Bush.

George Clinton and John Calhoun are the only two men to be VP for two Presidents.