Surface acoustic wave (SAW) technology can provide wireless, passive RF ID tagging and sensors. There are various embodiments using frequency and time diversity, and coded spread spectrum techniques, to meet different tagging and sensor applications. New research has shown that single frequency and multi-frequency CDMA tags can be used in a wide variety of passive wireless, multi-tag, space and commercial applications. This talk will discuss the current research and technology used for SAW yags and sensors, and describe current tag-sensor technology for space and other applications. The use of coding and spread spectrum techniques will show the advantageous of the technology and contrast to silicon RF tags.