The kinetics and mechanism of the acid‐catalyzed hydrolysis of di‐2‐chloroaniline phosphate ester were studied in 0.5–7.0 mol dm−3 hydrochloric acid at 80°C in 20/80 (v/v) dioxane–water medium. The log rate profile shows rate maximum at 4.0 mol dm−3 hydrochloric acid. The results show that di‐2‐chloroaniline phosphate is reactive mainly via conjugate acid species. Ionic strength data show a positive salt effect. The effect of different parameters such as temperature, solvent, and substrate concentration on the rate of hydrolysis was studied. Molecularity and order of the reaction have been supported by Arrhenius parameters, the Zucker–Hammett hypothesis. The rate values shown by experimental and theoretical computational hold good agreements in the entire acid range. © 2009 Wiley Periodicals, Inc. Int J Chem Kinet 42: 126–131, 2010