Thin strips of polyester type foams loaded with the complexing agent 1‐(2‐pyridylazo‐2)‐naphthol or PAN were used to preconcentrate trace amounts of cadmium from large volumes of water. This technique circumvents the need for auxiliary instrumentation and energy source. At 10 μg/L concentration of cadmium, in 670 1 of water, a relationship between the number of micrograms collected on the strips and time of immersion of the strips in the sample has been obtained. The deviation of this curve from linearity is explained.