Background: Very little is known about the prevalence of acquired brain injury (ABI) in Ireland. ABI prevalence has previously been obtained from Belgian general practitioners using a postal survey. We attempted to ascertain the prevalence of ABI in County Mayo through a postal survey of all general practitioners in the county.The specific objectives of this project were to:1. identify whether general practitioners area. aware of patients with ABI aged 18-65 in their practicesb. able to provide prevalence data on ABI in patients aged 18-65c. able to provide data on age, gender and patient diagnosis2. analyse prevalence of ABI from any available data from general practitioners.Methods: A pilot postal survey was performed initially in order to assess the feasibility of the study. It was established that general practitioners did have the necessary information required to complete the questionnaire. A main postal survey was then undertaken. A postal questionnaire was administered to all general practices in County Mayo in the west of Ireland (n = 59). The response rate was 32.2% (n = 19).Results: General practitioners who replied on behalf of their practice could provide data on patient age, gender and diagnosis. In the nineteen practices, there were 57 patients with ABI. The age-specific prevalence of ABI in the area surveyed was estimated at 183.7 per 100,000. The mean patient population per practice was 2,833 (SD = 950). There were found to be significantly more patients with ABI in rural areas than urban areas (p = 0.006). There were also significant differences in the ages of patients in the different ABI categories. Patients whose ABI was of traumatic origin were significantly younger than those patients with ABI of haemorrhagic origin (p = 0.002).Conclusion: Although this is a small-scale study, we have ascertained that general practitioners do have data on patients with ABI. Also, some prevalence data now exist where none was available before. These can be used to form the basis of a more substantial programme of university/community partnership research which could provide medical and psychosocial benefits for people with ABI and their families.