OBJECTIVE To ascertain the sources of information women use when making decisions about hormone replacement therapy (HRT). METHODS A cross-sectional, population-based computer-assisted telephone survey of 1082 randomly selected women aged 50-80 years (80.3% response rate) was conducted at Group Health Cooperative of Puget Sound, a large staff-model health maintenance organization in Washington state. RESULTS Overall, 460 participants (42.5%) were current HRT users, 226 (20.9%) were past users, and 396 (36.6%) were never users. Discussions with physicians dominated as the major source of information used in decision making by current (83.4%) and past (65.5%) users, but were less often cited by never users (44.4%); printed material was used by 44.5% of women. Although 72.1% of current users reported that the amount of information received from their physician about the benefits of HRT was about right, only 48.2% of past users and 33.6% of never users shared this view (P < .001 current versus never), and 13.3% of current users, 32.6% of past users and 58% of never users reported receiving no information from their physician about HRT's benefits. CONCLUSIONS Hormone replacement therapy use is strongly related to interactions between women and their physicians. Many women use written materials to make decisions about HRT. A large proportion of women feel inadequately informed about HRT's risks and benefits. Much work remains to be accomplished toward meeting the goal of the US Preventive Services Task Force that all perimenopausal and postmenopausal women be counseled about the potential benefits and risks of HRT.