Acute viral bronchiolitis (AVB) is the most common lower respiratory tract infection in the pediatric population, characterized by self-limited evolution and variable severity. Among the support alternatives, high-flow nasal cannula (HFNC) is indicated for mild to moderate cases due to its physiological effects. Objectives: To evaluate the success of HFNC in infants diagnosed with AVB and describe the evolution of vital signs after support installation. Methods: Retrospective longitudinal study. Infants diagnosed with AVB who used HFNC as primary support over a 30-month period were selected. Data related to HFNC, vital signs, and clinical outcomes were collected. HFNC success was defined as no replacement of therapy by mechanical ventilation. Data were analyzed by male/female patient groups and HFNC success/failure. Results: 151 cases of AVB using HFNC during the period. Of these, 57% were male; median age was 6 months; weight 8kg; incidence of RSV infection 35%, and associated pneumonia 23%. Vital signs improved from the first reassessment, and within 24 hours, they were normalized for age. The median duration of HFNC use was 4 days, and the hospitalization period was 8 days. HFNC success rate was 75%. Conclusion: HFNC achieved a high success rate for ventilatory rescue in moderate bronchiolitis, with a positive clinical response observed within the first few hours of therapy. Moreover, within 48 hours of support, patients showed parameters considered readiness for weaning.