A new study of the composition of the Eltville Tephra is performed for the three sites Lixhe/Belgium, Ringen/Germany and Eltville/Germany (previous stratotype). This tephra is a precise stratigraphical marker dated at about 20 ka and intercalated in situ in Upper Weichselien loess in Belgium, The Netherlands and Germany. Since most of the authors have identified the Eltville Tephra after its dark grey colour in yellowish loess body, the correlation has in some cases been doubted so that geochemistry of the material should be used to take position. We analyse the pyroclasts and the mafic minerals of the tephra (clinopyroxene, olivine and amphibole). The volcanic glass is totally altered to illite, but the minerals show a clear basaltic alkaline magmatic signature. The tephra resulted from a strong initial activity of a basaltic volcano. The origin of the tephra would be the East Eifel volcanic field.