A model for the positive columns of dc low‐pressure discharges in Cs&sngbnd;Ar mixtures, which includes radial depletion of Cs ground‐state atoms and radiation trapping, is presented. The available experimental data for this discharge system were extended in such a way that comparison could be made between model calculations and experiments for a wide range of discharge currents and Cs vapor densities (0.2 × 1019−3.0 × 1019m−3) and a reasonable agreement is obtained.