BACKGROUND: Any tissue injury results in an inflammatory response by the body. During this inflammatory process, different changes in the body (called acute-phase response) occur in different organs and systems remote from the inflammatory focus. This response is associated with a change in the concentration of a large number of plasma proteins called acute-phase proteins – CRP, albumin, prealbumin, transferring, etc. METHODS: A prospective study on the CRP levels was carried out in the Clinic of Anesthesiology and Intensive Treatment monitoring the CRP levels dynamics in 30 VAP patients from the 1st to the 20th day in order to assess the severity and the possible prognosis on the outcome of the disease. 30 patients aged 57.3 years on average were monitored and assessed by means of the APACHE II scoring system >20.We review the dynamics of the CRP levels in surviving patients and the CRP levels of patients who died. RESULTS: The CRP levels of the patients studied are significantly increased (from 20 to 100 times higher than normal). There is a tendency to stabilize the CRP levels around the 5th-7th day of the treatment. After the 10th day the CRP levels increase in patients who died later and decrease in surviving patients. CONCLUSIONS: These features of the dynamics of the CRP levels in patients with VAP can be used as an element for assessing the effect of the therapy and a prognosis of the treatment outcome.