Background: Some aspects of the pathophysiology of complications in multiple-trauma patients still remain unclear. Mediators of inflammation have been postulated as playing a key role in being responsible for life threatening complications of multiple trauma patients. The objective of this study was to evaluate the prognostic value of procalcitonin (PCT) level in multiple trauma patients. Methods: A prospective study took place including patients with multiple trauma hospitalised in several hospital units. PCT level was measured in blood from 45 patients, aged 18-70 years using enzyme-linked immunoassay. The patients were divided into three groups: group I -individuals with multiple trauma with central nervous system injury; group II -those with multiple trauma without CNS injury; and group III -patients with isolated central nervous system injury. Results: Initial PCT levels were below 0.5 ng mL -1 regardless of the cause of trauma. In the 24 th hour of observation, a statistically significant increase of PCT concentration vs. initial levels was recorded in all groups of patients. Then PCT levels decreased significantly at the 3 rd measurement point in all groups, and they remained unchanged until the last measurement. The highest levels of PCT were observed in multiple trauma patients without CNS injury (group II). In this group of patients, a significantly longer duration of surgery in the post-trauma period affected PCT levels. PCT concentrations in patients who died were significantly greater than in survivors. Conclusions: A long lasting elevated concentration of procalcitonin in the post-traumatic period, or its repeated increase, is a good marker of developing complications observed earlier than clinical manifestations.