The transient retention of an anionic surfactant below the critical micellar concentration flowing in an argilo-calcareous sandstone is shown to depend mainly upon: (1) the dissolution of trace amounts of calcium carbonate contained in the sandstone and (2) precipitation and redissolution of the surfactant with calcium ions due to carbonate dissolution or ion exchange on the clays. The adsorpiton process on solid surfaces is secondary, due to a high pH resulting from the presence of carbonates. A predictive model is developed. It is compared with typical surfactant breakthrough curves and demonstrates that dissolution of calcite is the main process affecting the transport of surfactant close to the injection point. Notation Molar concentrations of ions or molecules are denoted by their chemical symbols with the exeption of T -(surfactant). Ca2+,Na+, . = cations in solution Ca2+, Nafcations fixed on solid ion-exchanger C,, = molar concentration of feed solutions Dhydrodynamic dispersion coefficient Jnumber of mixing cells in series K,..,6 = equilibrium constants L = column length M = mass of soil in the column HE = ion exchange capacity Pe -Peclet number Q = volumetric flow rate ttime