This research is part of an on-going project of the Sociedad de Estudios Vascos (Eusko Ikaskuntza) to technologically characterize Copper, Bronze, and Iron Age ceramics from Navarra (NE Spain). A total amount of 44 pottery samples from 8 archaeological sites were analyzed by Total Reflection X-ray Fluorescence (TXRF). In addition, two exploratory multivariate statistical techniques were used for approaching the compositional variability of this assemblage. Generally speaking, the statistical treatment allowed the recognition of two distinct compositional groups. A separate grouping appears to be created by Copper and Bronze Age samples, whereas the other is formed by Iron Age ones. According to previous petrographical data, the different compositional profiles of Iron Age ceramics are related to the addition of a temper composed of piroxenes, epidotes, and feldspars derived from ophitic rocks. These results let us propose that the nature of such a temper causes the alteration of the compositional profile provided by the rest of the pottery samples.