Previous analyses of dairy farm structural change focused on the variation over time in one or a small number of regions. Here we present an EU-15-wide analysis of the change of the number of farms in different size classes. The purpose is (1) to identify the differences in regional development patterns and (2) to measure the explanatory relevance and effect of key factors suggested in the literature. Apart from the unprecedented scope, the underlying Markov chain analysis also contributes by combining observed transitions in micro data with macro data on farm numbers. Results show widely significant impacts of most explanatory variables, but also reveal the complexity of the underlying processes.