This article aims to study the consequences of the phenomenon named brain drain or migration of human capital flight and loss of productivity. Thus, it can also generate positive effects such as exports of technological capital and generation of Foreign Direct Investment (FDI) in the country of origin. This topic was developed through the theory of social networks which axis consists in that the scientist from the developing country chooses his/her related network, that has the environment to develop productivity, which is in developed countries, and then decides to emigrate. Subsequently, the situation of migration is deepened under the concepts of brain drain and brain gain, which are analyzed by different authors who expose their different points of view, claiming that the brain drain generates negative repercussions for the ejector economies and gains for the receiving economies, thus, there are others who claim that it generates positive consequences for both the sending and receiving economies. The graphs show the brain drain index in Latin America and Caribbean countries, led by El Salvador, which indicates the loss of high skilled human resource in the continent. The study concludes that, if the scientist from the developing country emigrates under certain conditions to the developed country, s/he can generate brain gain in both the sending and receiving economies.