Gerald Ford, Ronald Reagan, George Bush Sr., Bill Clinton, Barack Obama.
This despite the fact that only 10% of the people in the country are left-handed.
In the previous 200 years there were only two presidents known to be left-handed - James Garfield and Harry Truman.
A New York Sun article discusses this interesting anomaly and speculates about why there has been an apparent surge in lefties; there may be biological and behavioral components, but it's probably just a statistical oddity.
Reposted from 2008.