BACKGROUND To determine the incidence of0 associated with mechanical ventilation in patients admitted to a service in a second level hospital NICU. METHODS Retrospective analytical study records of newborns admitted to NICU room and receiving mechanical ventilation in a secondary hospital health care. Demographic data, of mechanical ventilation, intubation and complications reported in the clinical record were collected and analyzed in SPSS 20. RESULTS 53 patients selected a total of 40 complications found. The annual incidence of pulmonary complications associated with mechanical ventilation in the area of service neonatology NICU, at a second level hospital at Sonora was 49.05% (95% CI 0.35 to 0.62). The most frequent pulmonary complications were atelectasis 35%, pneumonia 27.5%, pneumothorax 15%, bronchopulmonary dysplasia 15%, pneumomediastinum 15% and pulmonary hemorrhage 2.5%. CONCLUSIONS The presentation of pulmonary complications secondary to mechanical ventilation in neonatal patients is similar to that reported in developing countries. Atelectasis is the most common pulmonary complication in neonatal patients undergoing mechanical ventilation.