The depletion interactions between macroions caused by the addition of a highly asymmetric electrolyte (micelles) were studied using the integral equation technique. The three-component system contained the following species : macroions (component 1), charged micelles (2), and an equivalent number of small counterions (3). The ions are present as soft charged spheres, and thus the three species differ widely in charge and size. We showed that the model, reproduces the major features of reported experimental results (Sober, D. L.; Walt, J. Y. Langmuir 1995, 11, 2352), i.e., (i) the purely repulsive interaction between two macroions in simple electrolyte solutions, (ii) the onset of the attractive minimum above the critical micelle concentration, and (iii) the appearance of structural oscillations at high concentrations of added micelles.