This article takes as its starting point the idea of modernity in Brazil and its deployment in Brazilian society by means of an authoritarian project that values the "whitening" of the country. In this sense, we will discuss, albeit briefly, the concept of modernity. To explain the phenomenon of modernity through authoritarianism, we will focus on the concept of authoritarian nationalism. The racial issue is the focal point of the discussion, so we will present a synthesis of Brazilian social thought from the mid-19th century to the 1930s, in order to deal with the idea of eugenics in Brazil and the reception of European racist theories in that country.582838