In 2004, the board of Eastern Norwegian Regional Health Authority (HelseØst RHF) decided that medical audits should be carried out in the treatment of cerebral stroke and breast cancer and in the mental health services. The objective was to establish to what extent the best practice is followed, to learn from each other, and to obtain help and advice. The medical audits were based on guidelines in ISO and were carried out under the leadership of external medical audit leaders, medical experts and medical auditors from the region. The results show that, on the whole, the patients are offered satisfactory treatment, but improvement is needed. The number of breast-preserving operations could be increased, treatment should be offered in a cerebral stroke unit to all those with acute cerebral stroke and suicide assessments should be improved. Most improvement measures were started quickly and were followed up by directors and local boards. HelseØst RHF followed up the general improvement suggestions. The medical audits were well received by health enterprises. In order to carry out medical audits the following is needed; national medical standards or summarized information on the best practice where standards are not defined. The regional health enterprises can use medical audits to assess the standard of treatment in risk zones, thus ensuring that uniform services are available for the population. Medical audits provide a good tool for preserving quality.