A needs assessment survey of 2800 registered nurses in a major metropolitan area was performed to identify: (1) knowledge about breast cancer risk and screening; (2) attitudes toward cancer prevention and early detection; (3) practice of breast cancer control activities; and (4) perceived barriers to practice. Responses from 1,117 nurses were obtained. Nurses reported knowledge deficits regarding breast cancer risk factors (36%) and signs and symptoms of breast cancer (35%). Compared with physicians, nurses reported more favorable attitudes toward cancer prevention and early detection. More than 85% of nurses believed that nursing had a role in breast cancer screening and early detection, and 60% believed that nursing activity in this area would increase in the future. The most common breast cancer control activity performed by nurses was assessment of breast cancer history (61%). The least frequent early detection activity was performance of a breast examination (27%). Approximately 50% of nurses taught women about breast self-examination and mammography. Common barriers limiting practice included work setting obstacles (64%), knowledge and skill deficits (57%), lack of patient education materials (51%), uncertainty about nurses' versus physicians' role in breast cancer control (52%), and time constraints (42%). It is important to note that 70% of nurses viewed themselves as resources for breast cancer screening and early detection, particularly in reducing fears and misconceptions about cancer, assessing and informing patients about individual cancer risk, and developing a plan for screening. Based on the results of this survey, nurses may represent a key potential resource for implementing breast cancer screening and early detection activities if barriers limiting practice can be overcome.