According to the advanced technology information, varieties of information are increasing disseminated on the Internet. In particular, health information is contained in web site in order to gain knowledge, give opinions from experience and advertise health products and clinics. Although those webs are rapidly increased on the Internet but there is no guarantee that how credible the health information or health web is. Thus the purposes of this research were 3 folds: to (1) survey the credibility of Thai health webs, and (2) analyze the process of health web development. This study was employed 2 research approaches: (1) survey approach by examining credibility of 255 webs, based on study criteria from 1,888 Thai health webs. These data were analyzed by using frequency and percentage (2) qualitative approach by interviewing 30 webmasters regarding how to develop health web. The qualitative data were analyzed by using content analysis method to explore the process of web development. The majors’ findings were as follows: 1. Findings from the survey, twelve criteria of a web credibility were used to examine the webs. There were 99.20 % of health webs via the Internet proposed health information with legal or/and ethical contents. There were 77.30, 71.80, and 71.80 % of health webs giving an e-mail address of a webmaster and contacting channel for users, and provide successful links to other sources respectively. However, few health webs (9%) were given a disclaimer. Other criteria including date of creation, date of last update, references, and authors were disclosed on the webs only 12.20, 13.70, 32.20, and 33.30% respectively. 2. According to interviews, webmasters reported 7 steps of web development: (1) Beginning with individual interest, the initiation of developing a health web was started with an interest to create Thai health web after exploring health webs from other countries via the Internet. (2) Learning to create web, webmasters learned how to create a web by asking experts or self studying. (3) Letting aims and target group, some webmasters developed health webs for providing health information to public while some wanted to advertise their health products or clinics. Thus, the target groups of those health webs are general people and health care personnel. (4) Developing web patterns, some webmasters created a web by themselves whereas some hired experts to develop it. (5) Searching information, webmasters used variety of sources, such as individual expertise, experience, and other experts, and so on to collect health information. (6) Transforming data, after collecting enough health information, webmasters would transform those data from using technical terms to be general terms for people understandable in the patterns of new articles, cut and paste articles, and questions and answers column. (7) Updating information, this step, webmasters would regularly or irregularly update their health information. Comparing data between from survey and interviews, it was found that most webmasters less realized to show the credibility of health information and health web. In addition, some webs were not screened inappropriate language and or disconnected contents before posing new information on the Internet.