Aromatase inhibitors (AIs) increase the risk of bone loss and fracture. Guidelines recommend routine bone density screening for women on AIs, but there are few data regarding the incorporation of these guidelines into clinical practice. We assessed bone density testing in a community-based cohort of breast cancer patients treated with AIs. By means of encounter and pharmacy data from WellPoint plans in the HealthCore Integrated Research Database, we assessed bone density testing among 9,138 women aged ≥50 years with breast cancer who were treated with AIs between 2002 and 2008. We used multivariable logistic regression to identify factors associated with baseline bone density testing in women initiating an AI, and among a subset of 2,086 women treated with AIs for at least 2 years, with testing during the first 2 years of therapy. Only 41.6 % of women underwent bone density testing when initiating AI therapy. Rates of bone density testing increased over time, but were lower for women who were older, lived in the Northeast (vs. other regions), had been treated with prior proton pump inhibitor or tamoxifen therapy, lived in areas with lower educational attainment, or were enrolled in a health maintenance organization (vs. other insurance types) (all P < 0.05). Among women treated with AIs for at least 2 years, 59.9 % of women underwent bone density testing during the first 2 years of AI therapy. Rates of testing were lower for women living in the Midwest or West (vs. Northeast), living in areas with lower education levels, enrolled in health maintenance organizations (vs. other insurance types), and with prior tamoxifen use. In conclusion, most women initiating AI therapy, and 40 % of those on long-term therapy, did not undergo recommended bone density evaluation in this community-based population. Attention is needed to insure that unnecessary fractures are avoided in breast cancer patients taking AIs.