Two sulfonated surfactants, dodecylsulfonate (DSO) and dodecylbenzenesulfonate (DBS), were readily intercalated into MgAl layered double hydroxides (LDHs) using the co-precipitation method. Surface properties of DSO-LDHs and DBS-LDHs were modified from hydrophilic to hydrophobic characteristics. Surfactant aggregates occupying LDHs interlayer regions behaved similarly to that of surfactant micelles. Both DSO-LDHs and DBS-LDHs sorbed the nonionic hydrophobic organic pesticide, chlorpyrifos. Results demonstrate that chlorpyrifos was successfully retained in the hydrophobic region of DSO-LDHs and DBS-LDHs, with two distinct interlayer conformations. The nature of chlorpyrifos and surfactants, and supramolecular structure of surfactant-modified LDHs were responsible for differences in the conformations resulting from pesticide-incorporated LDHs. (c) 2005 Elsevier B.V. All rights reserved.