AbstractThe kinetics of catalytic and non‐catalytic hydrolysis of cis‐epoxysuccinic acid have been studied. The hydrolysis leading to tartaric acid has been found to proceed much faster in the presence of iron (III) catalyst than the reaction without a catalyst or with tungstate catalyst. A complex of the form {cat · H2E} between iron(III) salts (catalyst) and epoxysuccinic acid seems to be responsible for the main catalytic effect. On the other hand, the reaction has been found to be retarded by the product of hydrolysis, tartaric acid (H2T). The inhibiting effect was caused by the formation of a catalyst deactivating complex in the forms {cat · H2T} and {cat · 2H2T}. A mathematical model for the overall process has been developed and the mechanism of reaction discussed.