Introduction: Nurses are in a unique position to have a positive effect on an infant's ventilation therapy and complications protection because they maintain a continuous presence at the infants’ bedside and perform related tasks. Thus this study was done aimed to determine the conformity rate of nursing cares regarding to respiratory system in neonates under mechanical ventilation in neonatal intensive units(NICU) with the standards. Method: In this cross-sectional descriptive study, 100 nursing care regarding to respiratory system were observed by time sampling and event sampling. Data collected using a checklist included standard cares regarding to respiratory care, which was developed according to existing standards. Content Validity Index (0.95) and inter rater coefficient reliability (ICC=0.98), were calculated for checklist. Data collection method was observation and docomentation of checklist’s items which carried out in NICU of Mahdiyeh, Mofid and Emam Hosein hospitals affiliated to Shahid Beheshti University of Medical Science. Data were analyzed through descriptive statistics using SPSS software version 21. Results: Conformity rate of nursing cares regarding to respiratory system in neonates under mechanical ventilation in NICU with developed standards, was evaluated 59.27 percents and quality of nursing cares was moderate. The most of the conformity rate with standars (94%) conformiting of ventilator setting with doctors’ orders and documenting its’ amounts and the lowest (1%) correct adjusting of SPO2 alarm limit was evaluated. Conclusion: According to Nursing cares regarding to repiratory system are the most common cares and results indicated moderate level in compare with standars thus Authorities should pay attention to causes of noncomformity with standard cares and eliminate them for increasing health of hospitalized neonates, decrease complications and followed it, decrease length of stay as well as costs.