The proposed breast cancer project will measure the extent of underuse of efficacious breast cancer treatments among patients of the hospitals serving East and Central Harlem and other minority communities in lower Manhattan. We will first interview physicians and patients about their reasons for omission of efficacious adjuvant treatments. At the 6 participating hospitals, we will then implement an intervention consisting of: a) computerized reminders to prompt surgeons to refer patients for adjuvant treatment, and b) an individual to track referrals for and receipt of adjuvant treatments. We will assess racial/ethnic differences in rates of underuse and explore racial differences in reasons for underuse.