A foot sensor alarm for wheelchairs, detects if a wheelchair occupant's foot has fallen off of a wheelchair footrest. The sensor and alarm make a wheelchair occupant or care giver aware that a foot has fallen off of one or more of the footrests. Sensors may include contact closure sensors, with snap-action switches or magnetically actuated reed switches can be used. Battery-operated window alarms with piezoelectric sound emitters send out vibratory or audio sounds as alarms. An occupancy sensor seat pad is used to power up the alarm system. A flashing light emitting diode can be wired in parallel with each sound emitter to provide a visual alarm as well.