Abraham Lincoln, James Garfield, William McKinley and John F. Kennedy are the four U.S. presidents to be assassinated, as of 2015. In all, there have been 16 assassination attempts on U.S. presidents.
Abraham Lincoln was the first U.S. president to be assassinated. He was shot and killed by John Wilkes Booth at a theater on April 14, 1865. James Garfield was shot and killed by lawyer Charles Guiteau on July 2, 1881, just four months into his term as president. William McKinley was shot and killed by Leon Czolgosz on Sept. 6, 1901. McKinley's assassination led to Secret Service providing protection for presidents. John F. Kennedy was the last president to be assassinated, on Nov. 22, 1963.