Sustainability transitions are commonly considered impossible without regime change. Theoretical work on regime change has mainly focused on niches and landscapes and less on change ‘from within’. Empirical analysis helps theorising endogenous regime change. Conceptualising regimes as semi-coherent entities composed of multiple ‘institutional logics’, we analyse the endogenous regime change in Dutch dairy farming. Practices in this sector have become more and more market-driven. This dominant logic however was increasingly challenged by institutional logics centring round cultural identity and sustainability. Tensions particularly centred round the increased indoor housing of cows. The contestation of this practice eventually led to a first ‘crack’ in the regime, as it weakened the dominance of the market logic and enabled opportunities for more sustainability. Our case study shows that the presence of alternative institutional logics is necessary to crack the regime, but opportunities to patch it back together are similarly crucial to enable sustainability transitions.