There are only a few studies in the literature investigating the effects of gestational age on developmental dysplasia of the hip. The aim of this study was to investigate the effects of gestational age on hip ultrasound findings in the early neonatal period in preterm newborns born between 30th and 36th weeks of gestational age. Between January 2008 and December 2013, a total of 788 hips of 394 premature newborns with a gestational age of up to 36th weeks who underwent hip ultrasonography in the first week of their life were retrospectively examined. The distribution of roof angles and hip types in terms of sexes was compared between groups. Birth weight, birth height, a, and beta angles were analyzed in terms of the gestational age. The mean gestational age was 33.07 weeks (SD 2.09; between 30th and 36th). Six hundred and seven hips were classified as type I, 154 as type IIa, 21 as type IIc, and 6 as type III. In the 30th week, type IIc hips in females and type III hips in males were statistically significantly higher (P=0.001). In the 34th week, type IIc hips in males were statistically significantly higher than the females (P=0.013). In the 35th week, type IIa hips in females hips were statistically significantly higher than the males (P=0.008). Among all preterm infants, type IIc hips were more common in the 30th, 31st, 32nd, and 34th weeks, whereas type III hips were statistically significantly more common in the 30th week (P=0.0001). The 30th, 31st, 32nd, and 34th weeks of age are gestational ages that should be considered in terms of dysplastic and subluxed hips in premature newborns. Copyright (C) 2018 Wolters Kluwer Health, Inc. All rights reserved.