British and Dutch urban policies have advocated housing diversification and social mix in neighbourhoods subject to urban renewal. Question marks have been placed against the evidence base for the assumed social effects of diversification. This paper provides a review of research into the actual consequences of diversification in Great Britain and the Netherlands. After a brief policy discussion, the paper identifies five issues for which evidence is reviewed: housing quality and area reputation, neighbourhood-based social interactions, residential attitudes towards social mix, the role-model effect, and problem dilution.