Enforcement of the Packaging Directive 62194 has required the development of reliable reference methods for the determination of heavy metals in glass. After considering Pb, Cd and Hg TC2 has undertaken a collaborative study for the determination of hexavelent chromium. In this recommended procedure the glass sample is digested with a mixture of sulphuric acid and ammonium hydrogen fluoride at room temperature, then diphenylcarbazide is added to form a violet complex which is measured with a spectrophotometer. Decomposition efficiency, matrix effect and interferences produced by foreign ions are discussed. For container glasses of common production no alteration of the chromium valence state was highlighted due to the dissolution process. This is not assured for glasses containing other redox pairs that should be examined case by case. The final round robin conducted on a glass containing given amounts of barium, did not reveal any significant absorption of hexavalent chromium on the low soluble salts that are formed during the dissolution process. The method is sensible down to 2 mgCr6+/kg of glass.