The relationship between statin use and cancer risk has been evaluated in numerous observational studies and as a secondary outcome in randomized controlled trials evaluating the effects of statins on cardiovascular outcomes. Although there are plausible biologic mechanisms to suggest that statins could inhibit cellular proliferation, the epidemiologic data do not show a consistent reduction in cancer risk among statin users. Despite the current lack of evidence for a chemopreventive effect, there are several methodologic considerations in the studies reported to date that prevent a definitive conclusion that statins do not reduce cancer risk. Given the widespread use of statins, continued monitoring of their risks and benefits is warranted.