Abstract: A removable step climbing assembly that includes a number of longitudinally separated, confined space defining pairs of brackets alternately located on opposite side of a vertically extending rigid member, such as a mast of a ship or the like. A pair of step defining units are provided each of which units includes a pair of longitudinally spaced flanges that may removably and concurrently engage the confined spaces of two of the pairs of brackets on opposite sides of the elongate member. As a person climbs up or down the elongate member, the step defining units are sequentially removed from the brackets in which they are supported and moved to adjacent free bracket to permit the person to use the units as steps in ascending or descending the elongate member. Resilient triggers are provided that automatically interlock with the bracket to prevent inadvertent disengagement of the step defining unit therefrom.