Pathophysiology of sepsis is characterised by a whole body inflammatory reaction and concurrent activation of the host's anti-inflammatory mechanisms. The balance between pro- and anti-inflammatory reactions is critical for the outcome of the patient. Strongly activated phagocytes and high levels of proinflammatory cytokines occur in patients who are at risk of developing circulatory shock and multiple organ dysfunction. Extensive anti-inflammatory reaction, which is characterised by the presence of high levels of circulating anti-inflammatory cytokines and impaired innate and adaptive immune functions, renders critically ill patients prone to secondary infections. Evaluation of the immune-inflammatory status on admission to the hospital may be helpful in the early identification of patients who are bound to develop organ dysfunction. Such patients could possibly benefit from a mode of therapy aimed at modifying the course of inflammatory response. The use of inflammatory markers may also improve diagnosis of severe infection. The present review summarises the studies on markers of inflammation and immune suppression used, first, as predictors of organ dysfunction in patients with systemic inflammation, and, second, as indicators of infection in adults and neonates.