Abstract: A height adjustable work support assembly to be used primarily as an integral part of a stepladder. It includes a work support tube (1) with interchangeable platform bases (10). The work support tube extends downward through the top of the ladder (2), and is held in position and guided by a pivoting lock plate (3) attached to the top of the ladder by a supporting plate (4). A pivoting guide bushing assembly located at a lower level, supports the tube (1) in the vertical position. The lock plate (3) and guide bushing assembly can be pivoted upward/downward with the closing of the ladder, permitting the work support tube (1) to be pivoted and held within the confines of the folded ladder. When the work support tube is pivoted, the spring loaded locking washer (6) locks the work support tube in the reverse direction, preventing it from sliding out of the ladder while storing or transporting.