A simple, environmentally friendly, economical and sensitive method for the determination of trace cadmium has been proposed. The method utilised flow injection on-line solid phase extraction coupled with flame atomic absorption spectrometry (FAAS). Determination was based on the adsorption of cadmium(II) ions on a mini-column packed with Chelex-100 at pH 7. The influence of eluent composition and concentration, pH of the solution, and flow rates on the preconcentration and elution steps were investigated. The effects of alkaline, earth alkaline and some transition metal ions on the adsorption of cadmium on Chelex-100 were also examined. The detection limit and recovery for cadmium were 17 ng L-1 and 100-104%, respectively. The proposed procedure was successively applied to the determination of cadmium content in black tea samples and in the following reference materials: stream sediment (GBW07310), sewage sludge (CRM144R), and sea water (CASS-4).