Abstract: Temperature and motion detection system (TMDS) for detecting the presence of a living being, such as a baby or animal, left in a vehicle after the engine or electric motor has been shut off to help reduce harm or deaths from extreme temperatures. The TMDS, or parts thereof, include the ability to sense and differentiate ambient vehicle passenger compartment or cabin temperature from that of the living being (body heat) and also sense the presence or the motion of the living being. Upon comparing sensor inputs, or parameters related thereto, to one or more limits programmed or set for, or by, a control unit of the TMDS, the system activates alert subsystems in the vehicle, such as the alarm, horn, lights/flashers, lowering electric windows, unlocking doors, or the like to help decrease the occurrence of deaths when temperatures approach dangerously high or low values.