The risks and benefits of hormone therapy (HT) in the treatment of postmenopausal women remain controversial. In this population-based, observational study, we documented health outcomes among postmenopausal Australian women using HT. Women aged 60-80 years were recruited into the Geelong Osteoporosis Study 1994-7 and followed over a median period of 6.6 years. Mortality, and the development of vascular events, breast and colorectal cancers were documented for 67 HT-users and 521 non-users. Median duration of HT-use was 5.0 years (IQR 3.0-10.0). There was no excess in all-cause mortality associated with HT-use. Based on 92 deaths (six HT-users, 86 non-users), the adjusted odds ratio (OR) for all-cause mortality was 0.79 (95%CI 0.32-1.97). With 99 reports of vascular events (13 HTusers, 86 non-users), the adjusted OR for vascular events was 1.30 (95%CI 0.66-2.57). There were insufficient numbers of breast or colorectal cancer cases (21 breast cancer cases, all non-HT users; and 7 colorectal cancer cases, one HT-user and six non-users) to adequately calculate the risk associated with exposure to HT. Although the sample size was small, these results do not support an association between HT and mortality, despite a possible link between HT and increased risk of developing vascular disease.