Abstract: A modular power drive wheelchair is provided for rapid assembly and/or disassembly of relatively compact modular components. The wheelchair comprises a base module including a base frame and related support wheels, wherein the base frame is adapted for facilitated mounting or dismounting of a seat module. A battery module including at least one storage battery is provided for relatively easy slide fit mounting onto the base frame at a position below the seat module. A controller module is also provided for mounting onto the base module and functions during wheelchair operation to control battery powered operation of one or more drive motors coupled to the wheelchair wheels. The various modules are designed for rapid disassembly to permit easy transporting of the wheelchair, for example, within the trunk of a standard automobile. Moreover, the base and seat modules are designed for relatively easy size adjustment to accommodate changing size requirements, for example, of a growing child.