The first president to die in office was William Henry Harrison, he died after contracting pneumonia. Upon his death, John Tyler became president. The second president to die in office was Zachary Taylor, who died of acute gastroenteritis. His successor was Millard Fillmore. President Warren G Harding also died due to natural causes, he had a heart attack, and Calvin Coolidge became president. The most recent president to die due to natural causes was Franklin D. Roosevelt, who died of a brain hemorrhage. Upon his death, Harry Truman became