BACKGROUND AND AIMS OF THE STUDY Short-term glutaraldehyde-fixed autologous pericardium is widely used in cardiac valve repair or in autologous pericardial bioprosthesis construction. The thinner the tissue, the better the fixation. The aim of this study was to determine thickness and useful surface area of pericardium in relation to harvesting site using a digital thickness counter (0.01 mm precision). METHODS Parietal pericardium fragments were obtained from the pericardial sac of six fresh cadavers (group I). In the other groups, pericardial strips (80 x 30 mm) were obtained from patients undergoing surgery: group II patients (n = 5 females) and group III (n = 10 males) were non-cardiomegalic (cardiothoracic ratio (CTR)<0.5), while group IV patients (n = 5) were all cardiomegalic (CTR >0.5). RESULTS Results were reported on a coloric scale according to measurement position. In group I, mean surface area was 93+/-18 cm2, and thickness gradually increased from 0.1 to 0.6 mm, maximally on the diaphragm, along the left heart side. In other groups, a gradual increase in thickness was identified towards the diaphragmatic zone. Significant differences in tissue thickness appear as a result of cardiomegaly, but are not related to the sex of the patients. CONCLUSIONS Pericardium taken from the right anterior aspect of the pericardial sac in patients without cardiomegaly is the most appropriate tissue for valve reconstructive surgery, due to its thin nature and hence better fixation properties.