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The leaching of metals from waste printed circuit boards (WPCBs) in cupric chloride solutions (HCl–CuCl₂–NaCl) was studied. Effects of initial concentration of cupric (8–157 mM Cu²⁺), chloride (0.7–2.0 M NaCl), temperature (20–80°C), solids ratio (1–15 w/v) and air/oxygen (1 L/min) on the leaching of copper as well as other metals (i.e. Fe, Ni, Ag, Pd and Au) were investigated. The findings have shown that increasing the initial concentration of Cu²⁺ leads to a significant enhancement in the metal extractions. At Cu²⁺ concentrations of ≥ 79 mM, high extractions (i.e. ≥ 98%) for copper, nickel and iron were obtained over 120 min. An increase in the concentration of chloride (i.e. from 0.7 M to 2 M Cl⁻) decreased the extraction of copper by up to 40% at 60 min due to the decrease in the activity of free Cu²⁺. Rising the temperature from 20 °C to 80 °C resulted in a 1.38-fold increase in the copper extraction at 120 min …