Purpose: We aimed to compare the short-term outcomes of infants from our level IIIC neonatal intensive care unit (NICU) in two different periods. Method: In this cohort study, data from preterm infants (≤29 weeks and birth weight <1500 g) registered in the Vermont Oxford Network (VON) system were divided into two periods, the first period between January 1, 2005, and December 31, 2009, and the second between January 1, 2010, and December 31,2019.Results: There was no difference in the distribution of preterm infants according to their gestational age subgroups (p=0.169). Although the survival rate increased significantly in the second period (48.1% vs. 64.3%, (p<0.001), there was no difference in terms of survival without morbidity (p=0.480). Conclusion: Analysis of NICU data, through rigorous methods may provide opportunities for the development of quality improvement projects to improve the quality of health care in developing countries.