An analytical method, SSMS, for the determination of trace impurities in cobalt is described. This element is used as raw material for the production of60Co in Embalse Nuclear Power Station. Tin, aluminum, lead, silicon, molybdenum, calcium, vanadium, boron, chromium, zirconium, tungsten, nickel, magnesium, iron, zinc and copper were determined. Manganese, analyzed by AAS, was used as an internal standard. The measurements were semiquantitative. The accuracy of the results was compared with that of emission spectrography and atomic absorption spectrometry, the agreement was found to be satisfactory.