Inoceramid shells (four individuals) from deep facies sediments of the Plentzia Formation) (Santonian, Basque Arc) have been analysed to determine their elemental chemistry (Mg2*, Sr2*, Na+, Ba2*, Fe2* and Mn2*) using the electronic pròbe' microanalyse'r. Relationships between the luminescent behaviour of the selected inoceramids and their elemental chemistry (obtained from eight transects with a ¡total of 1235 ana:iyses) have been established. Results, indicate that Mg2*'and Sr2* keep higher values tat the medium shell layer, where luminescènce isj,ess intense. By contrast, Fe2+ and Mn-* are considerably higher at both the outer andJnner shell layer and inter-prismatic zones, where luminescence exhibits the highest colour intensity (bright-yellowish). On the other hand, Na* and Ba2* do not show a clear relationship with the luminescent behaviour of the analysed inoceramids, as their variations along the transects do not follow the luminescent changes of the shells. Therefore, it is suggested that in spite of the deep burial suffered by the sediments, which deeply overprinted the elemental chemistry of the shells, Na* and Ba2* profiles could still preserve patterns close to the originals