Abstract: A mobile ladder has a base, castors mounted to the base, a ladder connected to the base, a support member connected at one end to the base and at the other end to the ladder forming a structural triangle between the members, the ladder including a floor engaging member affixed thereto. The connection of the ladder to the base includes a link member which also forms a step of the ladder, pivotally mounted to the base about a first axis, and the link is also connected to the ladder about a pivot having an axis parallel to the first axis. The link is adapted to pivot about the first axis such that the ladder, if it follows an arc between the first position where the ladder is engaging the floor in frictional contact therewith and a second position whereby the ladder pivot with the link is passed over the gravitational dead center above the first axis and the ladder is cleared of the floor.