Purpose: Research on EMI (English-Medium Instruction) has addressed the extent to which content lecturers speaking in their L1 perform as well as when they lecture in English. In this study a lecturer who gave the same lecture in his L1 (Catalan) and English was observed to examine if and how transitioning from one language to another impacts his use of metadiscourse. Methodology: Drawing on Adel's taxonomy (2010), data from four lectures were obtained to compare the quantity and quality of metadiscursive items in the L1 and EMI lectures. Findings: Findings show that the lecturer made a similar use of metadiscourse across languages of instruction, suggesting that EMI does not always affect the use of metadiscourse. A closer analysis of the content of the lectures suggests that metadiscourse seems to be determined more by the complexity of the lecture content rather than by the language of instruction. Value: These results substantiate the need for bespoke training that accommodates to different lecturer profiles in terms of English proficiency, pedagogy and the complexity of the content to be taught.