Abstract: A power-assisted wheelchair is disclosed that is particularly well suited for use by a person capable of exerting some hand/arm force in attempting to propel the wheelchair while seated therein, but incapable of exerting sufficient force, at least in some instances, to achieve satisfactory overall non-assisted operation of the wheelchair. Power-assist is provided by an electrical power unit that includes a motor for driving each main wheel of the wheelchair, with the power unit being removable to facilitate folding of the wheel chair when not in use. Motor energization is initiated when the user exerts force on the hand rims, connected with the drive wheels, in an attempt to propel the wheelchair. Displacement of the handrim relative to the associated drive wheel caused by the user exerted force is sensed and an electrical signal is produced to cause motor energization, with structure and feedback circuitry also being included for enhancing the efficiency of the power assist thus provided.