This article analyses ethnic discrimination in Mexico relative to Chile, Colombia and Peru from a perspective of horizontal inequality. It presents the numerous ways in which such discrimination is perpetuated and shows how far back in history segregation reaches, having taken root in the period of conquest by European nations before becoming entrenched in the colonial era and institutionalized in the constitutions that gave rise to the Latin American republics and in the formal and informal institutions shaped since then. Notwithstanding progress with recognition of political, social, cultural, collective and territorial rights and the creation of institutions to implement anti-discrimination policies, there is a large and enduring social debt. This article also identifies some divides and, by way of policy implications, suggests certain measures for closing them.