Abstract <p>The effect of the cobalt(II) speciation on its distribution parameters was studied for different types of sorbents. Inorganic sorbents based on hydrolyzable elements have shown the highest selectivity to Co in neutral and alkaline media (pH 7–10). The experiments on the cobalt sorption onto KU-2 strong acid cation-exchange resin at pH 3–5 have demonstrated the presence of Co²⁺, which shows high affinity for all the sorbents studied. In neutral and weakly alkaline media, the inorganic sorbents adsorbed Со(ОН)⁺ and Со(ОН)₂⁰ hydroxo complexes due to heterogeneous ion-exchange reaction (surface complex formation). The appearance of the <i>S</i>–pH dependences for the inorganic sorbents suggests higher stability of cobalt hydroxo complexes at microconcentrations as compared to the published data. In the whole pH range studied, cobalt(II) showed a behavior of an inert sorbate with all the inorganic sorbents studied.</p>