Although cancer is a major cause of morbidity and mortality in most nations, the spectrum of cancer occurrence varies substantially worldwide. Most previous epidemiologic studies investigating cancer etiology were conducted in North American and western European countries that are relatively homogenous in terms of cancer spectrums and many lifestyle exposures. These limitations may have hindered these studies from evaluating some important etiologic hypotheses. From 1996 to 2000, the Shanghai Women's Health Study recruited 74,942 adult Chinese women from selected urban communities, with a 92% response rate. All participants completed a detailed baseline survey and anthropometrics. Approximately 88% of cohort members donated a urine sample (n = 65,755) and a blood (n = 56,832) or exfoliated buccal cell (n = 8,934) sample. Noteworthy characteristics of this cohort include low consumption of alcohol (1.9%) and use of tobacco (2.4%); high intake of fish (mean, 50.8 g/day), soy foods (mean, 142.3 g/day), and certain vegetables; low prevalence of obesity (5.1%); and nearly 100% employment outside the home. Currently, this cohort of women is being followed via biennial in-person recontact and periodic linkage to cancer and vital statistics registries. The resources from the cohort will be valuable in future studies of environmental exposures and biomarkers for the risk of cancer and other chronic diseases.