Countries need epidemiological information about population injury statistics to devise preventive strategies. To generate such information we estimated the one-year incidence and distribution of injury in a group of 87,134 adult Sukhothai Thammathirat Open University distance-learning students residing throughout Thailand. Those who participated joined the study by filling out a baseline questionnaire in 2005 which included a one-year recall of injuries serious enough to interfere with daily activities and/or require medical treatment. The more serious injuries were categorised by location, mechanism and intentionality. We collected sociodemographic information about the participants. Nearly 22% of participants reported at least one injury during the previous 12 months. Males, those with lower income and the less educated, had higher injury rates. Home injuries were more common among females. Sports, road and workplace injuries were more common among males. Transport injuries decreased with age and falls increased with age. Most injuries were unintentional. Injury rates among Thai adults are high. We identified at risk groups by injury mechanism and setting. Before interventions can be devised more research is needed regarding exposure and vulnerability in at risk socio-demographic groups.