Cyclodextrin-mediated capillary electrophoresis has been developed for separation and analysis of chlorinated as well as substituted phenolic compounds. The procedure used a negatively charged sulfobutylether-β-cyclodextrin (SB-βCD) to effect differential partitioning of the phenols between the buffer and CD phases. In 50 mm phosphate buffer containing as low as 1 mm SB-β-CD, 25 phenolic compounds including 11 Environmental Protection Agency (EPA) priority phenols were separated with theoretical plate numbers well above 100 000, for 50 cm of effective length in most cases. An equilibrium complexation model was used for investigating the effect of pH as well as different cyclodextrin concentrations on the electrophoretic mobility. The cyclodextrin-mediated capillary electrophoresis system was also applicable for separating and quantifying the level of pentachlorophenol in contaminated soil samples.