Chemical synthesis of bioactive peptides has become a widespread and rapidly growing technique due to automated and efficient protocols for chain assembly. For most applications, the crude synthetic product must be purified to remove residual reactants, failure sequences and chemically modified peptide species. We propose here a method of universal applicability based on immobilized metal ion affinity chromatography, CNBr cleavage and use of reversible Met-sulfoxide protection. With this method we were able to purify to homogeneity in high yield the PbCS 242-310 polypeptide corresponding to the C-terminal region of Plasmodium berghei CS protein.