Abstract: A height adjustable tanker access platform system having a fixed frame member, an access platform operatively mounted on the fixed frame member for vertical movement with respect to the fixed frame member, and a drive mechanism operatively engaged between the fixed frame member and the access platform so as to provide for raising and lowering of the access platform, is disclosed. The drive mechanism comprises a drive means securely mounted on a fixed frame member, a drive pulley operatively connected to the drive motor to permit selective driven rotation of the drive pulley about a first rotational axis, and a main idler pulley rotatably mounted on the access platform for rotation about a second rotational axis. A drive cable is securely attached at an anchored end to the fixed frame member and securely attached at an opposite remote end to a vertically moveable counterweight.