BACKGROUND: To understand how health care delays may affect breast cancer detection, the authors quantified changes in breast-related preventive and diagnostic care during the coronavirus disease 2019 (COVID-19) pandemic. METHODS: Eligible women (N = 39,444) were aged ≥18 years and received a screening mammogram, diagnostic mammogram, or breast biopsy between January 1, 2019 and September 30, 2020, at 7 academic and community breast imaging facilities in North Carolina. Changes in the number of mammography or breast biopsy examinations after March 3, 2020 (the first COVID-19 diagnosis in North Carolina) were evaluated and compared with the expected numbers based on trends between January 1, 2019 and March 2, 2020. Changes in the predicted mean monthly number of examinations were estimated using interrupted time series models. Differences in patient characteristics were tested using least squares means regression. RESULTS: Fewer examinations than expected were received after the pandemic's onset. Maximum reductions occurred in March 2020 for screening mammography (-85.1%; 95% CI, -100.0%, -70.0%) and diagnostic mammography (-48.9%; 95% CI, -71.7%, -26.2%) and in May 2020 for biopsies (-40.9%; 95% CI, -57.6%, -24.3%). The deficit decreased gradually, with no significant difference between observed and expected numbers by July 2020 (diagnostic mammography) and August 2020 (screening mammography and biopsy). Several months after the pandemic's onset, women who were receiving care had higher predicted breast cancer risk (screening mammography, P < .001) and more commonly lacked insurance (diagnostic mammography, P < .001; biopsy, P < .001) compared with the prepandemic population. CONCLUSIONS: Pandemic-associated deficits in the number of breast examinations decreased over time. Utilization differed by breast cancer risk and insurance status, but not by age or race/ethnicity. Long-term studies are needed to clarify the contribution of these trends to breast cancer disparities.