Abstract: A foldable bicycle includes a frame, gears and two wheels. The frame includes a front vertical tubular portion, a front horizontal tubular portion, a hinge, a rear horizontal tubular portion and a seat-supporting tubular portion. A lopsided portion is disposed above the front fork. One piece of the hinge is welded to the rear end of the front horizontal tubular portion, and another piece is welded to the front end of the rear horizontal tubular portion. The seat-supporting tubular portion is positioned by a positioning rod. Therefore, the foldable bicycle of the present invention may be folded up into a smallest volume and then may be stored away easily through its positioning unit, hinge and positioning rod. Also, its two small wheels fitted to the rear rack enable the bicycle in a folded condition to be moved around easily.