Purpose: Most of the information accessible on the Internet is not only useless, but also may be false or misleading. This is of greater significance about medical information that seems alarming. Thus, the purpose of the study was to examine the quality, level of readability and coverage of health information of Persian-language websites concerning diabetes. Method: The study was applied in terms of its purpose and mixed method in terms of nature where content analysis method was used. In the study, the websites on diabetes were reviewed using the Discern checklist, Gunning Readability Index and the interviews were conducted with the patients admitted to the website for information about their illness. Results: The results showed that the readability of the websites on diabetes is not so desirable. The credibility of the information was largely undesirable. The quality of diabetes sites was not so desirable. Moreover, the overall ranking of publication sites regarding diabetes is moderate. Additionally, the results of the interviews showed that the quality of information about diabetes and the quality and structure of the website were evaluated from three aspects of drug information, information proportionality and overlapping of important information. Discussion and Conclusion: Given the low readability, undesirable quality and credibility of information on diabetes websites, providers and professionals should try to provide websites with simple, understandable, and relevant information for the entire society.
