This study aimed to identify factors associated with maternal attachment of breastfeeding mothers, with a focus on the mothers' breastfeeding characteristics. Methods: Data were collected from 217 mothers who breastfed their healthy baby for 1 month after childbirth and had no postpartum complications. The data were analyzed by hierarchical regression analysis. Results: The factors significantly associated with maternal attachment were an emotional exchange with one's baby (β=.41, p<.001), breastfeeding confidence (β=.20, p=.022), depression ('quite a bit or more', β=-.18, p=.005), and depression ('a little', β =-.14, p=.024). The model explained 38.4% of variance in maternal attachment. Conclusion: In order to improve attachment, nurses should be actively supported in helping mothers in the first month postpartum adapt to breastfeeding. Interventions to prevent postpartum depression should also be conducted.