The purpose of this study was to determine factors influencing general practitioners' (GPs) commencement of hormone replacement (HRT) in perimenopausal women referred for bone mineral density analysis. GPs who referred 80 untreated healthy perimenopausal women to a Western Sydney teaching hospital for osteoporotic fracture risk assessment were surveyed. All patients underwent dual energy X-ray absorptiometry of the lumbar spine, femoral neck and distal radius. Subjects were reported as 'at risk of fracture' if their bone mineral density was more than two standard deviations below the mean of young adults. Patients had normal (n = 55) or reduced (n = 4) bone mineral density at all sites; 21 subjects (26%) had regional osteoporosis. HRT was commenced in 35 women. A multivariate logistic model showed that menopausal symptoms (OR 173.9, p < 0.001) and reduced bone mineral density at any site (OR 28.3, p < 0.001) were highly significant independent factors predicting HRT (R2 0.48). Other clinical features such as low weight, family history and smoking status did not contribute further to GP decision making.