The enantiomers of six phosphoroamidothioate pesticides have been separated by high performance liquid chromatography on a cellulose tris (3,5 dimethyl phenyl carbamate) chiral stationary phase (Chiralcel OD). The influence of composition of mobile phase was investigated, and the probable chiral recognition mechanism has been described. The enantiomers of six phosphoroamidothioate pesticides have been separated by high performance liquid chromatography on a cellulose tris (3,5 dimethyl phenyl carbamate) chiral stationary phase (Chiralcel OD). The influence of composition of mobile phase was investigated, and the probable chiral recognition mechanism has been described.