So far there were eight US presidents who have died or were assassinated while in office, and here we go with the full list.
1. William Henry Harrison (March 4, 1841 – April 4, 1841)
2. Zachary Taylor (March 4, 1849 – July 9, 1850)
3. Abraham Lincoln (March 4, 1861 – April 15, 1865)
4. James A. Garfield (March 4, 1881 – September 19, 1881)
5. William McKinley (March 4, 1897 – September 14, 1901)
6. Warren G. Harding (March 4, 1921 – August 2, 1923)
7. Franklin D. Roosevelt (March 4, 1933 – April 12, 1945)
8. John F. Kennedy (January 20, 1961 – November 22, 1963)