Despite data demonstrating the safety of omitting axillary surgery in older women with early-stage breast cancer, the incidence of axillary surgery remains high. It was hypothesized that the prevalence of nodal positivity would decrease with advancing age. The National Cancer Data Base was used to construct a cohort of adult women with early-stage, clinically node-negative, estrogen receptor-positive (ER+), human epidermal growth factor receptor 2-negative breast cancer treated between 2013 and 2015. Multivariable logistic regression was used to assess the relationship between age and nodal positivity, and this was stratified by the axillary surgery category. Modified Poisson regression was used to estimate the proportion of women receiving adjuvant therapy according to age and nodal status. The incidence of axillary surgery among women aged 70 and older (n = 51,917) remained high nationwide (86%). There was a significant decrease in nodal positivity with advancing age in women with early-stage, ER+, clinically node-negative breast cancer from the youngest cohort up to patients aged 70 to 89 years, and this was independent of histologic subtype (ductal vs lobular), race, comorbidities, and socioeconomic factors. Overall, less than 10% of women aged 70 or older who underwent surgery had node-positive disease, regardless of axillary surgery type, and almost 95% of node-positive patients aged 70 or older were at pathological stage N1mi or N1. Axillary surgery may be safely omitted for many older women with ER+, clinically node-negative, early-stage breast cancer. Nodal positivity declines with advancing age, and this suggests varied biology in older patients versus younger patients. © 2019 American Cancer Society.