Who was the first U.S. President to have both parents living when he was elected President?

Nice guess, rubym, but it was Grant. (I had to do the research.)

"Just a few parents of Presidents survived to see their sons enter the White House, though most witnessed their early successes. The mothers of Washington, John Adams, Madison, Polk, Garfield, McKinley, Franklin D. Roosevelt, Truman, and Carter, the step mothers of Lincoln, Harding, and Ford, and the fathers of John Quincy Adams, Fillmore, Harding, and Coolidge survived through their children's inaugurations. Coolidge's father even enjoyed the unique privilege of swearing in his son.

In addition to these, both parents of Grant and Kennedy lived to see their sons assume the highest office in the land." http://www.nps.gov/history/history/online_books/Pr...

Ulysses S. Grant - Assumed office: March 4, 1869

Father: Jesse Root Grant (1794–1873)

Mother: Hannah Simpson Grant (1798–1883)

The only one I'm sure of off hand is Kennedy, Joe and Rose Kennedy were both alive through his term, although Joe Sr had a stroke during his son's term, but outlived him; and Rose Kennedy lived to be over 100. And of course, George HW Bush and Barbara Bush were both alive for George W's Presidency, and are today.

Before Kennedy, I don't know if there were any.