WASHINGTON -- Transportation Secretary Norm Mineta is stepping down from his Cabinet position.

Mineta, 74, is one of President George W. Bush's longest-serving Cabinet members. He has served in the position since Bush assumed the presidency in 2001.

He also served in President Bill Clinton's cabinet.

The former 10-term California congressman is the only Democrat in Bush's Cabinet and is the longest-serving transportation secretary in U.S. history, according to his official department Web site.

Mineta was plagued with back problems during his tenure as transportation secretary but has since recovered.

He was hospitalized for three months in December 2002 for back surgery and treatment of an infection. During that time he ran the department from a hospital suite reserved for top government officials, and some speculated that he might resign then.

Mineta's resignation is effective July 17, White House press secretary Tony Snow said Friday. Snow did not give a reason for the resignation.