SummaryStudies have been made of an electroless copper-nickel-phosphorus alloy from a citrate complex bath using hypophosphite as reducing agent and electroless copper-nickel binary alloy from a triethanolamine complex bath using formaldehyde as reducing agent. With an increase in copper content of alloy, the specific resistance of deposit decreased. The TCR of copper-nickel-phosphorus alloy increased remarkably because of the crystallization of Ni3P after heat treatment. But the increase in TCR of copper-nickel binary alloy was moderate and not so striking as for the phosphorus containing alloy.