This Small Business Innovation Research Phase I project will develop an ultrasensitive magnetic sensor technology capable of operation in an unshielded environment. These compact sensors will be based on superconducting quantum interference devices (SQUIDs) that are fabricated from high temperature superconducting materials. A collaborative effort between Magnesensors, UC Berkeley and IBM Research will employ a new design to produce high Tc SQUIDs operating in ambient fields with and unprecedented level of sensitivity. This technology will enable the development of an entirely new generation of instrumentations that will find use in a wide variety of applications including non-destructive evaluation of cracks and corrosion in aircraft, inspection of ICs, homogenous immunoassays using magnetic labels, environmental monitoring and so on.