In Austria, microcensus surveys on self-reported morbidity are carried out at regular intervals every ten years, generally by the Federal Statistic Centre. In the following, we describe an epidemiological observational service which could be regarded as an additional public health instrument. This service is termed "health monitor", and the SERMO (self-reported morbidity) study is the scientific project associated with it. The "health monitor" data provide information on the prevalence of various illnesses and impairment, characteristics and variables of background morbidity by repeated short-term representative surveys on self-reported morbidity. The health monitor permits continual observation of the background morbidity of an entire population, while scientific questions pertaining to the SERMO study can be investigated via the health monitor data base. Self-reported morbidity data provide important information about the health of a general population, in addition to clinical and mortality data, and help to make decisions in health policy. By collecting informations (e.g. nearly every month) on background morbidity, "health monitor" and SERMO project could complement other Austrian public health systems to measure the overall health of the population in general.