Background: Stretch marks are harmless skin disorders but can cause cosmetic and psychological problems. The mechanism in the pathogenesis of stretch marks is still not well known yet. However, it is most related to changes in the extracellular matrix components, including fibrillin, elastin and collagen. Skin hydration can affect the primary mechanism of its pathogenesis. This study determined the relationship between skin hydration and stretch marks.Methods: This was a cross sectional study with a total sampling method, involving 84 female residents from the Faculty of Medicine, Universitas Sumatera Utara batch 2020. The diagnosis of stretch marks is made through history taking and physical examination. The skin hydration checking was conducted on the right and left femur by using Corneometer CM 825 device. The data collected were analyzed by using the Kruskal Wallis test. The Ethical Committee of Universitas Sumatera Utara has approved this study.Result: The majority of ages ranged from 26-35 years (86,1%). Subjects who had a pregnant history with stretch marks were 44,6%. The majority of stretch marks located in the subjects were femur 45,5%. Skin hydration 65,5% of subjects was classified as dry. Skin hydration in subjects with stretch marks was lower than those without stretch marks with a p-value <0,001. There is a relationship between skin hydration and stretch marks with a p-value <0,001.Conclusion: There is a significant relationship between skin hydration and stretch marks.