Human type 1 T-cell lymphotropic virus (HTLV-1) infection has been described in many areas of the world, including Caribbean countries, Japan, Africa, Oceania and South America. In this review we defne the endemicity of HTLV-1 in the country proposing four epidemiological criteria. Then we discuss the core subject of the review, which is the vertical transmission of HTLV-1. This mechanism is one of the main forms of transmission in our country. Within the development of this particular topic, we present an estimated rate of vertical transmission and the risk factors associated to vertical transmission based on an exhaustive review of the national and international literature. This review pretends to provide a frst approach to the vertical transmission of HTLV-1, an aspect poorly studied in our country.