This article offers some theoretical-methodological considerations concerning 'mixedness'. It seeks to highlight the limits, pitfalls and derivatives of current literature with respect to the conceptualization of 'mixedness'. After a preliminary contextualisation (definition, variables and main patterns linked to the phenomenon of 'mixedness', endogamy and exogamy), the aim will be to draw attention to the different key levels of theoretical and methodological complexity of the phenomenon, with the purpose of avoiding simplistic or restrictive analyses. We will therefore put into question the clarity of the notion of “mixed union”, the direct equation between hybridity and social integration, and will emphasize the inherent complexity of the processes of configuration of the resulting (mixed) ethnic identity.