Future point-of-care (PoC) molecular-level diagnosis requires advanced biosensing systems that can achieve high sensitivity and portability at low power consumption levels, all within a low price-tag for a variety of applications such as in-field medical diagnostics, epidemic disease control, biohazard detection, and forensic analysis. Magnetically labeled biosensors are proposed as a promising candidate to potentially eliminate or augment the optical instruments used by conventional fluorescence-based sensors. However magnetic biosensors developed thus far require externally generated magnetic biasing fields and/or exotic post-fabrication processes. This limits the ultimate form-factor of the system, total power consumption, and cost. To address these impediments, we present a low-power scalable frequency- shift magnetic particle biosensor array in bulk CMOS, which provides single- bead detection sensitivity without any (electrical or permanent) external magnets. The sensor array system consumes a total power of 165 mW and occupies 2.95times2.56 mum2 in a 0.13 mum CMOS process.