Background and Purpose: Oxygen therapy is one of the common treatments for neonates with cardiopulmonary disease. The aim of this study was to evaluate adherence to oxygen therapy standards by nurses before, during and after using oxygen hood. Methods: In this cross-sectional study, 250 cases of nursing care were evaluated before, during and after administration of oxygen hood therapy in preterm infants. The observations were conducted according to the standards of the neonatal intensive care units (NICU) of hospitals affiliated to the Ahvaz University of Medical Sciences. The data collection tools included a self-designed checklist for nursing audit evaluating the performance of NICU nurses working by neonatal oxygen hood, and a demographic profile checklist. The data were analyzed by Chi-square and Spearman tests, using SPSS version 18. Results: The results demonstrated insufficient adherence to the standards of oxygen therapy by 90% of the nurses before neonatal oxygen hood. Moreover, regarding the mentioned standards, 84% and 99.2% of the nurses had moderate and poor performance during and after oxygen therapy, respectively. Conclusion: Considering the poor performance of the NICU nurses before, during and after oxygen therapy, appropriate supervision and training programs for nurses is recommended to promote their capabilities in this regard.