Objective: Menopause is associated with physiologic changes that may have negative effects on quality of life in some women and/or that may increase morbidity and mortality secondary to osteoporosis and/or coronary heart disease. Estrogen replacement therapy (ERT) and combined estrogen/progestogen therapy (hormone replacement therapy [HRT]) play an important role in reducing these negative effects. The North American Menopause Society (NAMS) sought to develop treatment algorithms that could assist the clinician in deciding whether to recommend ERT/HRT to postmenopausal women. Design: NAMS held a closed conference of experts to develop a decision tree that outlined the rational use of ERT/HRT in postmenopausal women on the basis of risks versus benefits. The proceedings of the conference were used to assist the NAMS Board of Trustees in developing this consensus opinion of the Society. Results: On the basis of the conference proceedings, NAMS developed three algorithms for the clinician to use as a tool in deciding whether to recommend ERT/HRT to a woman who is postmenopausal: (1) menopause-related symptoms, (2) cardiovascular risk, and (3) osteoporosis risk. Conclusions: The goal of ERT/HRT is to enhance women's quality of life as well as to reduce the risks of death and disability associated with osteoporosis and coronary heart disease. The decision to initiate ERT/HRT must be individualized according to each woman's needs. This decision tree for ERT/HRT presents a rational approach to decision making on the basis of the principles of care; details of specific therapeutic interventions will change as data from clinical trials are presented. (C) 2000, The North American Menopause Society.