BACKGROUND: HIV / AIDS is one of the most significant epidemics in the world; infection in children is the result of mother- to- child transmission in most of the cases. One of the proposed prophylaxis protocols recommends the administration of antiretroviral drugs, such as zidovudine, a drug that, among its side effects, causes anemia in a large percentage of patients who receive it. The aim of this study was to determine the frequency of anemia in newborns, perinatal exposed to HIV, who received zidovudine, at Hospital “Teófilo Dávila,” El Oro- Ecuador, in 2018. METHODS: Observational, descriptive and cross-sectional study, carried out with 50 full-term neonates, delivered by C-section, exposed to HIV, with antiretroviral treatment that includes the use of zidovudine, hospitalized in the neonatology service of Hospital Teófilo Dávila, located in the city of Machala, in 2018. RESULTS: Of the entire population, 56% (n = 28) of the sample were males. The presence of anemia (hemoglobin ˂10g/dl) was demonstrated in 28 (56%) of the 50 patients in the sample, among patients with anemia 75% (n = 21) had normocytic anemia, 64% of the anemias (n = 18) were normochromic. CONCLUSION: 56% of the neonates exposed to HIV during pregnancy who received zidovudine, developed anemia; most of these anemias were normocytic and normochromic.