Five experiments were performed to identify the basic Spanish colour categories (BCCs) and to locate them in the CIE L*u*v* space. The existence of 11 BCCs was confirmed using an elicited list task and a free monolexemic naming task. From the results provided by a synonymicity estimation task, it was concluded that, in Spanish, 2 synonymous terms ("morado" and "violeta") are used to name a category equivalent to the English category "purple." Three experiments provided information about the colourimetric localization of the 11 Spanish BCCs. Two experiments used monolexemic naming tasks (free and restricted) and a third required the free signalling of prototypes and good exemplars. It was observed that Spanish and British BCCs are essentially equivalents in number and colourimetric delimitation and, therefore, our work can be considered to extend and complement previous research (on English BCCs) insofar as achromatic categories in colour space localization, the links between chromatic and achromatic categories (red and orange have no direct links with achromatic categories), and the dependence of the use of BCCs on lightness are concerned. Lastly, our results indicate the existence of 2 categories that are nearly basic: beige and garnet. (Contains 4 tables, 6 figures, and 1 footnote.)