This talk aims at offering an overview of current empirical findings on CLIL in Spain across different educational levels: primary, secondary and tertiary. With respect to general proficiency, primary and secondary school children enrolled in CLIL programmes have been found to outperform children in traditional programmes. As for the tertiary level, research has focused on teacher discourse rather than on learning outcomes.With regard to particular areas of language competence, there are no so clear gains. Only reading, receptive vocabulary, writing and some morphological phenomena seem to be favourably affected by CLIL. Primary school research on productive vocabulary and Secondary school research on morpho-syntax and pronunciation do not reveal the superiority of CLIL participants. At the tertiary level, CLIL groups admit making more improvement as regards content, whereas NON-CLIL groups report more gains regarding language, which indicates that immersion programmes need to devote more attention to language form.In conclusion, the CLIL experience seems to be beneficial when learners are tested on general proficiency, though gains on specific language areas are not so conclusive. In addition, the investigation carried out at different educational levels is still extremely fragmentary, and a more integrated approach to CLIL research across educational levels is needed.