Background: In an age of antiretroviral therapy, the life expectancy of children perinatally infected with Human Immunodeficiency Virus (HIV) has significantly increased. At the same time, however, pulmonary pathologies secondary to opportunistic infections have decreased thanks to increased diagnostics and access to antiretroviral therapy (ART). Despite this, in these children an immune dysregulation is maintained due to chronic infection. There is evidence that these patients have increased probability of presenting with abnormalities in pulmonary function, mainly with chronic obstructive clinical pictures (25% - 40% of perinatally infected adolescents display some anomaly in the spirometry), which predisposes them to increased risk of chronic pulmonary disease. Since lung development occurs mainly during infancy, patients perinatally infected with HIV may suffer consequences. This can be secondary to opportunistic infections, chronic inflammation due to the virus, and immunologic effects of ART, mainly in non-industrialized countries, where late diagnosis is frequent. Methodology: An analytical, observational, cross-sectional study was conducted at Roosevelt Hospital Pediatric infectious disease clinic, from January to December 2019. A sample of 76 patients was obtained, out of a population of 362 patients. A total of 62 subjects, who met the criterion of reproducibility in the spirometry, were analyzed. Results were analyzed with percentages and the association of variables using the chi-squared test (χ2). Results: A decrease in pulmonary function was found in 34% of patients, mild obstructive pattern (16%) predominating. Significant association between basal viral load greater than 100,000 cp/ml and a decrease in Forced expiratory flow 25 - 75 (FEF 25-75) (p 0.046) and in relationship between forced expiratory volume and forced vital capacity (FEV1/ FVC p = 0.024) was observed, as well as a non-statistically significant relationship between advanced clinical stage at diagnosis and decreased pulmonary function. Conclusions: The prevalence of decreased pulmonary function related to advanced clinical stage and elevated basal viral load (>100,000 cps/ml) is higher than that reported in other studies (25%) and has an influence in the long-term decrease in pulmonary function.