The availability of low cost microprocessors is a major step towards practical Automotive Control Systems. Such systems also require sensing of physical parameters and transferring sensed values into and out of the processors. In some cases “Digital” sensors are practical and should be used. Other cases require analog sensors and Analog to Digital Conversion.Traditional methods of Analog to Digital Conversion, developed mostly for military and scientific applications, do not meet the needs of the Automotive Industry. These needs, including cost objectives, speed and accuracy goals and desirable features are outlined. Two circuits and approaches are recommended for Automotive Applications.The 4151/7151 is shown for single input relatively slow applications and the μA0850, a new monolithic IC, is described for complex multi-input control systems.It is concluded that analog sensors and Analog to Digital conversion can be economically applied when designed as an integral part of a microprocessor based system.