The aim of the study was to evaluate the presence and distribution of C-reactive protein (CRP) at the site of the abdominal aortic aneurysm (AAA) suck to determine its potential role in AAA ruptureMaterial and methods. Samples of abdominal aortic aneurysms were obtained from 16 patients during elective surgery. These samples were taken from three places at each three levels of the aneurysmal sack: the neck, at the region of maximum diameter and above bifurcation. The cryostat sections were immunostained for CRP visualization using a specific primary mouse monoclonal anti-C-reactive protein antibody. All the specimens were analyzed morphometrically. The data was analized as the ratio of the active surface of the specimen to its total surface in percentage value.Results. No statistically significant differences between CRP concentrations were found that depended on the site of the aneurysmal sack. However, there exists an average linear correlation between CRP concentration, which is defined as the ratio of the active surface of the specimen to its total surface in percentage value, and the thickness of the adjacent thrombus (Pearson's correlation ratio; r=0.42) with statistical significance of (p<0.00001)Conclusions. The detection of C-reactive protein within the aneurismal wall is not solely sufficient to determine its role in the destruction that eventually leads to a large abdominal aortic aneurysm rupture. It is necessary then to prove an association between not only the metabolism of CRP but also the complement system activation and inflammatory cells response.