The adsorption of cobalt, nickel, copper and zinc into microcapsules containing 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester was investigated. First, the particle size distributions, surface features as photographed by scanning electron microscopy and the amount of extractant contained were measured in order to evaluate the characteristics of the microcapsules. Next, the adsorption equilibrium and the adsorption rate were measured to estimate the adsorption mechanism of the metals. Finally, the separation of nickel and cobalt from a multi-component system using the microcapsules packed in a column was examined. The microcapsules prepared were found to be white and spherical. The adsorption equilibrium of each metal was found to follow the Langmuir adsorption isotherm. Both the complex formation reaction and the diffusion of the complex through the pores in the microcapsules were found to contribute to the overall adsorption rate of the metals. The separation of the metals by the microcapsule-packed column could be increased by decreasing the flow rate and increasing the height of the packed column. Separation of individual metals in an adsorption step was difficult, but in a desorption step the separation was possible by choosing a suitable solution for desorption.