Abstract: This article aims to examine the effect of intra-institutional conflicts in the European Commission on the extent of changes made to legislative proposals in trilogue negotiations. We develop and test three hypotheses related to how conflicts within the Commission, namely that intra-institutional disagreements during policy formulation (h1), and potential conflicts with previous (h2) or subsequent (h3) colleges of commissioners, increase the number of amendments to the Commission’s proposal adopted in trilogues. To test our hypotheses, we use a new dataset measuring the number of changes between Commission proposals and adopted legislation for 216 legislative acts negotiated between 2012 and 2019 by means of text-mining techniques. It is important to note that we control for differences between the Commission’s proposals and the co-legislators’ positions in order to distinguish between an effect on preferences anticipation and on the negotiations proper. Our results indicate that intra-institutional conflicts affect the Commission’s anticipation of the co-legislators’ positions. The effect on its behaviour in trilogues, that is, after the legislative proposal has been tabled, is less clear. Regarding the latter, only the number of Directorates-General involved is significantly linked with the number of amendments tabled. These findings suggest that while intra-institutional disagreements affect the Commission’s role in trilogues, the range of preferences is more important than the intensity of conflicts.