The correlations of benthic invertebrates, sediments and water quality were investigated at two stations in the Ell-Ren river of Taiwan by means of statistical analysis every two months during a one year period. A total of 8 aquatic insect species and 2 annelid species were collected. Based upon the statistical analyses, several significant correlations for the population of benthic invertebrates and heavy metal contents of sediment were found between Simulium sp. and “adsorptive and exchangeable” lead, Simulium sp. “bound to carbonates” copper as well as Baetis sp. and “bound to carbonates” chromium. Results of stepwise multiple regression indicated that the heavy metal contents of sediment could explain a considerable portion of the variance in the population of benthic invertebrates. “Adsorptive and exchangeable” lead accounted for 86.2% of the variance of the population of Simulium sp. while “Bound to carbonates” chromium retained 81.5% of the variance of the population of Baetis sp.