Diethylenetriamine, DETA polymer was used as a preconcentration of cobalt, iron and nickel prior to their determination by flame atomic. ab-sorption spectrometry (FAAS). Both batch-and column methods were used for the separation and concentration of above metals. These metals were quantitatively retained on the proposed adsorbent at pH 21 then were quantitatively eluted with 2 M hydrochloric acid or nitric acid. The recoveries of metal ions were greater than 98%. Detection limits (3 delta) were 1.5 g/L for Co, 2 . I g/L for Fe and 1.9 g/L for Ni. The relative standard deviations for the determinations were found to be 1.0-8.8%. The effect of Na on the preconcentration of trace metals has also been investigated. The method was applied to tap, ground and lake water samples.