Optimal conditions for Sn and Co codeposition were achieved in slightly acid citrate solutions containing no excess of ligand. Sn-Co coatings were deposited with amounts of Co ranging from 15 to 86 mass %. Bright deposits were obtained when the Co content exceeded 76%. These coatings may be considered as solid solutions of tin in alpha -Co and beta -Co. The beta -Sn phase is predominant in the case of coatings containing less Co. Voltammograms of the partial processes of Sn(II) and Co(II) reduction may be described quantitatively with the proviso that SnL2- and CoLH- are electrically active complexes.