A new solid-phase extraction method has been developed for the selective extraction of Cu(II) in an aqueous system using freshly precipitated lead diethyldithiocarbamate (Pb(DDTC)2) as a reagent. The method is based on the quantitative replacement of Pb(II) ions in the solid Pb(DDTC)2 phase by Cu(II) ions present in aqueous phase. The obtained solid Cu(DDTC)2 phase was dissolved in chloroform and determined spectrophotometrically at 435 nm. Beer’s law was obeyed over the concentration range of 0.2–5 mg dm−3. The molar absorptivity and the Sandell’s sensitivity coefficients of the solutions were 1.0689 × 104 dm3 mol−1 cm−1 and 0.0060 µg cm−2, respectively. The optimum conditions for each parameter were experimentally determined and possible interferences of various salts were also studied. The method has been validated and applied to determine Cu(II) in various alloys and water samples.