Abstract: The aim of this study was to identify the factors influencing the duration of spontaneous regression of Retinopathy of Prematurity. A prospective observational study was conducted over a duration of 1.5 years from December, 2019 to May, 2021. All the infants presenting with ROP or developed any stage later were considered for the study and were followed up as per International Classification of Retinopathy Guidelines (ICROP), 2005 guidelines till compete vascularisation. Data regarding the birth history and maternal factors were noted. In those neonates in whom the Retinopathy of Prematurity presented or progressed to type 1 ROP were treated and the rest were followed up till complete vascularisation and duration noted. Risk factors were compared in neonates undergoing spontaneous regression within 45 weeks PMA and those taking longer than 45 weeks. The Statistical analysis was performed by SPSS 23.0 version. Mean gestational age in neonates undergoing earlier spontaneous regression (<45 weeks) was 31.86±2.02 months, and that of delayed spontaneous regression group was 33±2.24 months. Mean birth weight in earlier spontaneous regression group was 1537.14±202.02 grams, and that delayed spontaneous regression group was 1406.19±229.88 grams. Mean duration of complete regression of ROP is 44.9 weeks postmenstrual age. Higher birth weight and Hyperbilirubinemia was found to significantly cause the regression of ROP within 45 weeks (P=0.021). Higher birth weight and Hyperbilirubinemia was found to cause earlier regression of ROP and hence could be a possible protective factor in the pathogenesis of ROP.