CLIL is currently enjoying a surge in popularity across the world in its cross-curricular form. While the structural difficulties in implementing CLIL are often recognised, there is little discussion of its inherent limitations. Focusing on cross-curricular programmes, this article analyses critically four of CLIL's central claims against the evidence of the latest research. The claims analysed are: CLIL leads to greater linguistic proficiency, it boosts motivation, it is suitable for learners of all abilities and it leads to greater intercultural awareness. The article concludes that while all four claims are, to a large degree, substantiated by the evidence, there are also clear limitations, stemming from theoretical and methodological shortcomings of the CLIL model, as well as from its interaction with contextual factors. The article suggests a number of ways in which these limitations can be addressed and concludes that, unless remedied, they could lead to an understandable yet regrettable disappointment with a model that is genuinely promising. (Contains 2 footnotes.)