Sound epidemiological data are a basic requirement for decision making on the allocation of health care resources. Unfortunately, this is not the case in Estonia, where the paucity of epidemiological data has impeded health care planning for rheumatic conditions. The current paper presents the first effort to explore the epidemiology of rheumatoid arthritis (RA) in Estonia. Electronic databases of all rheumatology units of Harju County, three national and one private, were searched for the records of RA (ICD-10 diagnoses M05 and M06.0) patients who had visited a rheumatologist during 2006 or 2007. Prevalence of RA was calculated for the age 20 years and older and for subsets according to age and gender, using the numbers from the patients' database in the numerator and the corresponding population numbers in the denominator. The total number of prevalent RA cases was 1,897, of which 85 % (n = 1,605) were women. The overall crude period prevalence 2006-2007 of RA in Harju County for the age group 20 years and older was 0.46 %. RA prevalence for both sexes increased with age until the age of 70-79 years and decreased subsequently. Prevalence of RA was significantly higher for women compared with men in all age groups. The prevalence of RA among women and men 20 years and older was 0.70 % (6.68-7.37) and 0.16 % (1.42, 1.79), respectively. Age-standardized (European population) prevalence rate was 0.44 %. The results are concordant with epidemiological data on RA prevalence derived recently in other European countries.