The extraction and stripping reactions of cobalt(II) by Cyanex 301 in Iberfluid diluent from aqueous manganese sulphate solutions has been investigated. The effect of different variables which should influence the extraction-stripping of cobalt was evaluated, including equilibration time, temperature, organic diluent, extractant concentration, aqueous pH, cobalt loading, strip solution concentration, etc. The number of stages required for the extraction and stripping of cobalt was also evaluated. The results were used to define the conditions for the purification of manganese sulphate solutions.