Magnetic sensors based on Giant Magnetoresistance (GMR) and Spin‐Dependent Tunneling (SDT) effects have high, frequency‐independent sensitivity. The small size and low power consumption of these sensors allow them to be used in multiple‐sensor arrays facilitating rapid scanning of an area in a single pass rather than raster scanning. This paper discusses the use of GMR and SDT sensors in NDE testing of surface cracks and features, deep cracks, and hole‐edge cracks as well as progress in X‐Y GMR sensors and multiple‐sensor arrays. © 2003 American Institute of Physics