Background. Users' acceptance and use of health IT are important factors to the success of health IT implementation. Thailand has implemented the national universal healthcare program and has been restructuring the country health IT system to support the program. However, there is no national data available regarding the penetration, acceptance and use of health IT in many healthcare facilities including the community health centers (CHCs).

Objectives. This research aims to answer three main questions: (1) how pervasive are health IT resources, IT knowledge, IT acceptance and use in CHCs? (2) how different is the pervasiveness among regions?, and (3) what factors predict CHCs' health IT acceptance and use?

Method. An observational research design was employed. A modified Unified Theory of Acceptance and Use of Technology (UTAUT) model was used to study CHCs' IT adoption. A random sample of 1,607 regionally stratified CHC's from a total of 9,806 CHCs was selected. Data collection was conducted using a cross-sectional survey by means of self-administered questionnaire. The research model was examined using the partial least squares (PLS) path modeling.

Results. With an 82% response rate, the data showed that people who worked in CHCs exhibited a high degree of IT acceptance and use. These results are similar in all of the country's geographic regions. However, there were perceived barriers using IT. The barriers are inadequate IT training, inadequate administration supports and unavailable internet connectivity. The research model analyses results suggest that IT acceptance is influenced by performance expectancy, effort expectancy, social influence and voluntariness. Health IT use is predicted by previous IT experiences, intention to use the system, facilitating conditions and Internet availability.

Conclusions. Health IT is pervasive and well adopted by CHCs in Thailand, but several perceived barriers associated with IT use were evident. The study results have implications for both health IT developmental efforts in Thailand and health informatics research. This study validated the UTAUT model in the field context of a developing country's healthcare system and demonstrated that the PLS path modeling works well in a field study and in exploratory research with a complex model.