Abstract: The platform assembly is a combination of step and toolbox storage space and can be easily installed and removed from the rungs of an extension ladder. The assembly includes a platform with angled vertical sides and hooked over the ladder side rails. The platform has a hinged lid with latch for access to the tool box attached to the bottom of the inward facing portion of the platform assembly. The tool box storage area is created by pieces of angled, plate, and flat bar aluminum. Two parallel downward angled pieces of aluminum on the bottom of the outward facing portion of the platform create a channel for the ladder rung to fit into as the platform assembly is installed on the extension ladder.