The aim of this systematic review was to identify types of approaches and methods used to evaluate the effectiveness of healthcare information websites. Simple usage data may not be sufficient to assess whether desired healthcare outcomes were achieved or to determine the relative effectiveness of different web resources on the same health topic. To establish the state of the knowledge base on assessment methods used to determine the effectiveness of healthcare websites, a structured search of the literature was conducted in Ovid Medline, resulting in the retrieval of 1611 articles, of which 240 met the inclusion criteria for the present review. The present review found that diverse evaluation methods were used to measure the effectiveness of healthcare websites. These evaluation methods were used during development, before release and after release. Economic assessment was rare and most evaluations looked at content issues, such as readability scores. Several studies did try to assess the usefulness of websites, but few studies looked at behaviour change or knowledge transfer following engagement with the designated health website. To assess the effectiveness of the knowledge transfer of healthcare information through the online environment, multiple methods may need to be used to evaluate healthcare websites and may need to be undertaken at all stages of the website development process.