Consumers are increasingly turning to the Web, expecting to find the latest health information. The purpose of this study was to assess the currency of online breast cancer information. We determined whether nine recent advances in breast cancer management were incorporated into 337 unique breast cancer Web pages. Two reviewers independently assessed content; if a Web page covered appropriate advances it was deemed to be 'current.' Of the 337 Web pages, 89 contained one or more advances. Of the 122 Web pages that had dates of update available, 49% had been updated within 6 months. Only 11%-37% of Web pages covered clinically accepted advances, even among Web pages that were updated after acceptance of the advance into clinical practice. We conclude that online health information is often not sufficiently current. Consumers searching for health information online should always consult an expert clinician before taking action.