Systemic inflammatory response syndrome (SIRS) was first described in 1991 as a group of syndromes which are easy to define clinically. SIRS should not be perceived as a diagnosis, but rather the clinical picture of changes in the levels of acute phase mediators, or a state of imbalance of the whole body in response to trauma, e.g. surgical trauma. For nearly twenty-five years subsequent generations of physicians have been trying to answer the question whether diagnosing SIRS in a patient makes sense, and if so, why. A number of published studies contain the evidence that the diagnosis of SIRS is associated with the following factors: development of single or multiple organ failure; increase in the incidence of deaths; longer hospitalization; longer stay in the Intensive Care Unit; development of infection, sepsis or severe sepsis. The overall conclusion is that the primary advantage of using SIRS as a prognostic scale is the ease and speed of testing for its criteria, and virtually no related costs. It has been repeatedly proven that it is in good correlation with the much more expensive and difficult prognostic scales, such as APACHE II, APACHE III, SAPS, ISS or MODS. Assessment of the criteria for systemic inflammatory response syndrome, feasible at the patient’s bedside, allows the physician to perform a swift selection of patients and recognize those with a higher risk of serious complications, thus introducing appropriate therapy, increasing vigilance and possibly performing subsequent extended laboratory tests.