Young women with breast cancer face treatments that impair ovarian function, but it is not known if malignancy itself impacts ovarian reserve. As more breast cancer patients consider future fertility, it is important to determine if ovarian reserve is impacted by cancer, prior to any therapeutic intervention. A cross-sectional study was conducted comparing if ovarian reserve, as measured by anti-mullerian hormone (AMH), follicle stimulating hormone (FSH), and inhibin B (inhB), differed between 108 women with newly diagnosed breast cancer and 99 healthy women without breast cancer. Breast cancer participants were ages 28-44 and were recruited from two clinical breast programs. Healthy women ages 30-44 without a history of infertility were recruited from gynecology clinics and the community. The median age (interquartile range) was 40.2(5.5) years for breast cancer participants and 33.0(4.6) years for healthy controls. The unadjusted geometric mean AMH levels (SD) for breast cancer participants and controls were 0.66(3.6) and 1.1(2.9) ng/mL, respectively. Adjusting for age, body mass index, gravidity, race, menstrual pattern, and smoking, mean AMH levels were not significantly different between breast cancer participants and healthy controls (0.85 vs. 0.76 ng/mL, p = 0.60). FSH and inhB levels did not differ by breast cancer status. In exploratory analysis, the association between AMH and breast cancer status differed by age (p-interaction = 0.02). AMH may be lower with breast cancer status in women older than 37. In younger women, AMH levels did not differ significantly by breast cancer status. Among the youngest of breast cancer patients, ovarian reserve as measured by AMH, FSH, and inhibin B did not differ significantly from healthy women of similar age. In older breast cancer patients, ovarian reserve may be adversely impacted by cancer status. These findings support the potential success and need for fertility preservation strategies prior to institution of cancer treatment.