Heavy metals in suspended sediments (SS) were investigated in the lower Chao Phraya River,Thailand, and Main particulate metals. The particulate fractions accounted mostly for 60-100% of total concentrations of Cr, Mn, Ni, Cu, Zn, and Pb in both dry and rainy seasons. The comparison of metal contents of the sampled SS and upper continental crust (UCC) implied some anthropogenic inputs of Cr, Ni,Cu, and Zn as well as the dilution process for those metals in the rainy season in Chao Phraya River. Enrichment factor in both rivers also indicated anthropogenic effects on metal content in SS,reflecting the distinctive seasonal process in Chao Phraya River and the spatial variation withinMaxil.