['To identify factors contributing to participation in breast screening in working women to drive health education planning and implementation.', 'Survey.', 'Automotive plants in southern Canada.', 'Union and nonunion women working in the plants.', 'Survey using "Health Care Practices: A Worksite Survey," modified for Canadian population.', 'Age, education, breast health practices, influences on decision to participate in breast screening, and physician gender.', 'Differences were noted among three age groups (under 30 years, 30-49 years, 50 years or older) in terms of influences and perceived barriers to the different modalities of breast screening. For clinical breast exams, women preferred an expert in breast health, regardless of whether the professional was a physician or a nurse. In all groups, the physician was noted as being very influential; however, perceptions of encouragement from the physician varied across the age groups. Perceptions of barriers to breast screening differed among the age groups and between women with male physicians and those with female physicians. Coworkers were identified as being a strong influence in the older group, whereas friends and family were identified as being more influential in the younger groups.'] Do working women identify influences and obstacles to breast health practices?