Biomagnetic methods, such as magnetoencephalography (MEG), magnetocardiography (MCG), and biosusceptometry, are becoming widely recognized for their unique and important capabilities. However, the high cost and impracticality of low‐temperature superconductor quantum interference devices (SQUIDs) has limited the dissemination of these methods, especially in countries where the cost of liquid helium is high. Several new technologies have the potential to change this situation. One is high‐temperature superconductor (HTS) SQUID technology, which has been pursued since the discovery of HTS materials in 1986. Another is optical magnetometry, which has received much attention since the report last year of a major breakthrough. In this paper, I will review the principles of operation of current and candidate technologies and discuss their future prospects. © 2004 American Institute of Physics