OBJECTIVE--To establish epidemiological data on the health problems within family practice in Iceland by multicentre analysis of well-defined geographic areas. DESIGN--Prospective practice audit. SUBJECTS AND SETTINGS--Thirteen Icelandic health centres (HC) with computerized contact data from 1 January - 31 December 1988. MAIN OUTCOME MEASURES--Health problems during one year in a population, as perceived by health care providers. RESULTS--A total of 176 384 health problems during one year in a population of 31 248, as perceived by the health care provider, were analysed. Musculoskeletal disorders accounted for 9.3% of all health problems (prevalence 210.6/1000 inhabitants), respiratory disorders 9.4% (189.9/1000), accidents 7.4% (203.2/1000), cardiovascular disorders 7.4% (112.0/1000) and mental disorders 6.1% (87.6/1000). The commonest single health problems were: hypertension, upper respiratory tract infections and non-articular rheumatism. The health problems accounting for the most frequent contacts were: mental disorders (4.0 contacts per individual per year), cardiovascular (3.7), and endocrine, nutrition and metabolic (3.2). CONCLUSION--Problem-oriented medical records from HCs, computerized in a uniform standardized way, can give extensive information about the content and burden of health problems in family practice and presumably public health. Our results are valuable because the population (the denominator) and the geographic study area are well defined. This information is an important part of clinical epidemiology and can be of great value for educators and health care planners.