Background: Mammographic density (MD), which reflects the amount of epithelial and stromal tissues in relation to adipose tissue in the breast, is a strong risk factor for breast cancer. Although diet is associated with breast cancer risk, studies evaluating the associations of adult diet with MD have mainly reported null associations. Few studies have, however, investigated the associations of dairy intake with MD, with conflicting results. Therefore, we investigated the associations of milk intake with MD in premenopausal women. Methods: We recruited 375 premenopausal women, with no history of cancer, who had routine screening mammography at the Breast Health Center, Washington University in St. Louis in 2016. We used Volpara to measure MD: volumetric percent density (VPD), dense volume (DV) and non-dense volume (NDV). In addition to known breast cancer risk factors, all participants completed a detailed questionnaire on milk intake (skim milk and 1%/2% milk were categorized into 4 groups: < once/week, once/week, 2-6 times/week, ≥once/day; whole and soy milk were categorized into 2 groups: < once/week, ≥once/week, because fewer women consumed them). We used multivariable linear regression models (adjusted for age, body mass index (BMI), parity, oral contraceptive use, family history of breast cancer, race) to evaluate the associations between milk intake and log transformed VPD, DV and NDV. Beta coefficients (β) were evaluated and back transformed for easier interpretation. Results: The mean age was 47.5 years (range: 32-58 years), mean VPD was 9.48%, mean DV was 80.69 cm³, and mean NDV was 1079 cm³. Compared with women who drank 1%/2% milk < once/week, VPD was 20% (p-value = 0.003) lower in the once/week group, 14% (p-value = 0.047) lower in the 2-6 times/week group, and 12% (p-value = 0.144) lower in the ≥once/day group. NDV was 19% (p-value = 0.039) lower among women who drank soy milk ≥once/week compared with women who drank < once/week. There were no associations of skim and whole milk with MD. Conclusions: We observed that 1%/2% milk intake was inversely associated with VPD, while soy milk intake was inversely associated with NDV. Further studies on how 1%/2% and soy milk intake impact MD are needed, as this could have implications in breast cancer prevention.