Abstarct: A rapid, highly sensitive and accurate procedure is proposed for the on-line preconcentration and determination of trace amounts of cadmium by flame atomic absorption spectrometry. By the passage of aqueous samples through a PVC column modified by 3-(2-thiazolylazo)-2,6-diaminopyridine (TADAP), Cd(II) ions adsorb. The retained Cd(II) ions are then eluted from the sorbent by 1.0 mol L−1 hydrochloric acid as eluent. Various influencing parameters such as pH, type and concentration of eluent for the stripping of Cd(II) ions from the sorbent, flow rate of sample and eluent were studied. The linear dynamic range of the method for 10 ml of sample was found in a concentration range of 2.0–40 µg L−1. The detection limit (DL) and enrichment factor were 0.7 µg L−1 and 52-fold, respectively. The relative standard deviations for 7 replicate determinations of cadmium(II) at the 5.00, 9.00 and 25.0 µg L−1 levels were 4.08%, 3.26% and 0.8%, respectively. For 10.0 mL sample volume, sampling frequency of 9 h−1 was obtained. The proposed method has been applied to the determination of Cd(II) at trace levels in water and soil samples with satisfactory results.