Abstarct: In this study, a sensitive on-line solid phase preconcentration coupled with flame atomic absorption spectrometric (SP-FAAS) procedure was developed for the determination of trace levels of lead (II) in different real samples. A mini-column packed with a chloromethylated polystyren functionalized with N,N-bis (naphthylideneimino) diethylenetriamine (PS-NAPdein) was used for the enrichment of trace amounts of lead from water samples. The preconcentrated Pb(II) ions was eluted from the mini-column using of 2.0M hydrocholoric acid. Chemical and flow injection variables were optimized for the quantitative preconcentration and determination of lead(II). Under the optimum conditions, calibration graph was linear over the rang of 0.008-0.2 micro-g/mlfor the preconcentration volume of 10.0 ml sample solution. The detection limit (DL) value for the preconcentration of 10.0 ml of sample solution was 0.005 micro-g/ml. An enrichment factor for a sample volume of 10.0 ml was obtained. The relative standard deviation for 6 replicate determination of lead(II) at the 0.02 , 0.10 and 0.20 micro-g/ml level were 4.8%, 2.0% and 6.3%, respectively. The effect of the presence of various species commonly associated with real samples was also investigated. The accuracy of the proposed method was demonstrated by analyzing different real samples.