The voltage modulation depths,&Dgr;Vof high-Tcdirect current superconducting quantum interference devices (SQUIDs) with resistors connected in parallel with their inductances were investigated. Both the junctions and resistors in the SQUIDs were fabricated using focused electron-beam irradiation. The effect of varying the resistor value (using focused ion-beam trimming) and the screening parameter&bgr;L(by varying the temperature and hence the junction critical current) were studied. Significant enhancement of&Dgr;Vrelative to an equivalent unshunted SQUID for&bgr;Lvalues up to 50 was observed, and the most effective shunt resistor value was found to be approximately equal to the junction resistance. ©1998 American Institute of Physics.