Using unused wires on VLSI chips for power supply decoupling including generating a VLSI chip design by: identifying floating wires in a VLSI chip; placing a via at each intersection between each floating wire and a power rail; determining a number of design rule violations for each via at each intersection; resolving the design rule violations for each via not on a major power rail; resolving the design rule violations for each via on a major power rail after resolving the design rule violations for each via not on a major power rail; after resolving the design rule violations for each via on a major power rail, identifying floating wires without a via; and for each floating wire without a via, identify an intersection with a least number of design rule violations and resolve the number of design rule violations by removing adjacent vias on adjacent wires.