We have fabricated a four-channel SQUID gradiometer system based on double relaxation oscillation SQUIDs (DROSs) with a reference junction. For a biomagnetic multichannel system, we simplified the DROS design by using a single reference junction instead of the reference SQUID. The SQUIDs were fabricated from hysteretic Nb/AlO x /Nb junctions using a simple four-level process. The DROSs provided very large flux-to-voltage transfers of typically 3mV/Φ 0 , enabling direct readout by a room-temperature dc preamplifier, and consequently simple flux-locked loop electronics were used. To realize a compact and reliable gradiometer, a first-order planar pickup coil was integrated on the same wafer with the SQUID. The flux noise of the gradiometer is about 5 μΦ 0 /√Hz at 100Hz, corresponding to a field noise of 8 fT/√Hz, measured inside a magnetically shielded room. A compact four-channel planar gradiometer system was implemented and operated to measure auditory evoked fields.