Retinopathy of prematurity (nROP) among extremely low gestational age newborns (ELGAN) in Slovenia has increased in recent years. At the same time mortality has further decreased and less invasive approaches for treatment of respiratory distress syndrome have been established. With the aim to study the possible association between the incidence of ROP and the duration of noninvasive ventilation, this retrospective study comprised ELGANs born during the first period (2010/2011), when invasive respiratory support was the prevalent method and in the second period (2015/2016), when noninvasive respiratory support was adopted. The results showed that the duration of noninvasive ventilation is a potential risk factor for ROP. Controlling for known risk factors for ROP and then adjusting for gestational age, number of transfusions and fraction of inspired oxygen (FiO2), the odds of ROP were 1.22 times greater (95% confidence interval, CI 1.01–1.48) with every additional week of noninvasive ventilation (p = 0.03).