This study investigates the formation of mixed marriages in seven European countries: the United Kingdom, France, Romania, Switzerland, Estonia, Belgium and Spain. While there is a growing interest in the spread and stability of mixed marriages, little research investigates inter-ethnic unions from a comparative perspective. Using individual-level longitudinal data from seven European countries and applying Poisson regression models, the study shows, first, that for several countries, the levels of mixed marriages vary more across ethnic groups within countries than between the countries. Second, immigrants from geographically and culturally distant origins show high levels of intra-group marriages. Third, marriage patterns among descendants of immigrants fall in between those of immigrants and natives, but for some groups endogamous marriages remain dominate.