This paper contributes towards a framework for analysing the effect of teaching Economics through a foreign language, in order to discover best practices that foster key content and language skills for Higher Education institutions following language bilingual programmes. The first part of the paper deals with the benefits and problems of implementation of Content and Language Integrated Learning. The central part of the paper outlines a two-year research project in the Faculty of Economics and Business at the University of Oviedo, Spain, giving details about the context and participants, methodology used to ensure learning quality, assessment programme for these methodologies, student perception, real language progression and the impact on academic results in the period 2012-2014. Module results are contrasted with a control group of Spanish-taught students who sit the same exam in their native language. Results show similar grades in both cohorts but a notable gap in higher bands. While attributed to linguistic shortcomings, we make a case for the added value of a second language and highlight how most students quickly progress towards nullifying that difference. The study, which has been applied to first-year modules, is adaptable and applicable to similar Economics-related degrees taught through English.