In the last decades, the number of bilingual schools in Europe has increased significantly. Most of these schools implement Content and Language Integrated Learning (CLIL) methodology in their teaching and, consequently, there is a demand for new and appropriate materials for each content subject taught through a foreign language: new textbooks written in L2 are needed, and the existent offer does not meet the current demand. Given that CLIL materials development is a relatively recent field, there is not much research on the evaluation of those still insufficient course books. In this paper, and in order to evaluate CLIL textbooks, we propose a tentative checklist twofold based: on the one hand, based on previous checklists created to evaluate ELT textbooks--CLIL materials use principles/techniques of foreign language teaching (Steirt and Masser, 2011)--,and, on the other hand, based on the criteria for producing quality CLIL learning materials drawn up by Mehisto (2012). Further research is in process in order to refine the checklist with the results of an analysis of the criteria carried out by a focus group of CLIL teachers, and of a survey addressed to teachers who are currently implementing CLIL in their schools.