Despite its recognized beneficial properties and successful application in many European educational systems, the CLIL teaching approach is rather unknown to Greek schools. Having not taken into account the ignorance and indifference of the Greek educational community towards CLIL and not looked into the reasons, we conducted a quasi experimental teaching of the CLIL model in a provincial high-school in Larissa, using a small sample of pupils, on the basis of a short-term environmental program. The aim was to indicate the receptivity and impact of the CLIL approach in Greek school environment. The description of this small scale CLIL project and the observation of its implementation are the objects of this case study, which showed that the learning results obtained converge with those identified in the foreign literature. This might suggest that the CLIL approach should not leave the educational community indifferent any longer, so as to actualize long-term implementation of the model in Greece as well. Lastly, it should be noted that, as long as the use of the methodology is in germinal stage, it is not possible for Greece to conduct quantitative surveys with large samples and many variables, but simple qualitative approaches, i.e. case studies and descriptions such as ours.