The present study aims to evaluate the quality of web-based information on gambling and to investigate potential content quality indicators. The following key words: gambling, pathological gambling, excessive gambling, gambling problem and gambling addiction were entered into two popular search engines: Google and Yahoo. Websites were assessed with a standardized proforma designed to rate sites on the basis of "accountability", "presentation", "interactivity", "readability" and "content quality". "Health on the Net" (HON) quality label, and DISCERN scale scores aiding people without content expertise to assess quality of written health publication were used to verify their efficiency as quality indicators. Of the 200 links identified, 75 websites were included. The results of the study indicate low scores on each of the measures. A composite global score appeared as a good content quality indicator. While gambling-related education websites for patients are common, their global quality is poor. There is a need for useful evidence-based information about gambling on the web. As the phenomenon has greatly increased, it could be relevant for Internet sites to improve their content by using global score as a quality indicator.