Since 1994 all Norwegian hospitals have to report events of deviance (i.e. events that caused or might cause harm to any patient) to the "Database for Reported Events" of the Norwegian Board of Health. In 1997 in total 4,433 events were reported, of these 620 had 'major negative effect to the patient', while 113 were classified as unnatural deaths. Huge differences exist in the frequencies of hospitals' deviance reporting, ranging from less than one to more than 100 reports per 100.000 patient days.The regulation by law to report any major deviance event, enforces the local quality improvements in the hospital. The dialogue within and with the hospitals is stressed, to ensure the continuous quality improvement 'within service'. The legal regulations cause fear of sanctions from national authorities — which is not the purpose for the national system for deviance reporting. So far, the obligation to report to the national database seems to stimulate and fertilise the local handling of deviance events within the hospitals, as the number of events reported is steadily increasing.A survey including all hospitals and their owners indicate that the hospital managers only to some degree actually use the experiences gained through deviance reporting to stimulate continuous quality improvement, as the feed-back loop is not used systematically. The knowledge on infirmities, reported as deviance events, is only rarely taken into consideration in long-term planning and budgeting by the hospital owners.