Background: Among women with chronic, preexisting mobility impairments, we sought to explore how their mobility difficulties affected the diagnosis and treatment of early-stage breast cancer Methods: This is a qualitative analysis of transcripts from in-depth in-person or telephone interviews with 20 English-speaking women who had early-stage breast cancer, were <60 years of age, and had chronic difficulty walking or used wheeled mobility aids at the time of their breast cancer diagnoses Results: Nine women were disabled by polio as children or had postpolio syndrome, 3 had cerebral palsy, 3 had spinal cord injury, and 5 had other conditions. Most women reported difficulty obtaining mammograms, primarily because of inaccessible equipment, positioning problems, and difficulties with uncontrollable movements. Many women made decisions about surgical approach and chemotherapy by explicitly considering how various therapies would affect their arms, which are essential to their mobility (they use ambulation aids, selfpropel manual wheelchairs, or otherwise rely on their arms for mobility or safety). Managing at home after surgery posed major mobility challenges, especially for women who lived alone. Several women reported feeling they suffered more chemotherapy side effects than do women without mobility problems. Weight gains with endocrine therapy compromised the mobility of several women. Conclusions: Increasing numbers of American women are living with mobility disabilities and entering age ranges with increased risks of breast cancer. Mobility impairments can affect women at every point during earlystage breast cancer diagnosis, therapy, and recovery. Clinicians must consider women's mobility functioning in making therapeutic recommendations to women with impaired mobility who develop breast cancer.