1. Fibronectins (FN) are believed to have a role in haemorheological perturbation associated with tissue damage. Fibronectins exist in two antigenically related forms, plasma (p) and cellular fibronectin, which has the extra domain sequences A (EDA) or B (EDB). The present study was designed to determine changes in plasma p-FN and EDA + FN under different types of surgical stress. 2. Sixty-two patients were divided into three groups: (i) group A, 33 patients undergoing hepato-pancreato-biliary surgery; (ii) group B, 19 patients undergoing laparoscopic cholecystectomy; and (iii) group C, 10 patients with postoperative complications. Plasma FN and EDA + FN levels were measured in these patients undergoing different types of surgical operation and either with or without liver cirrhosis using an enzyme-linked immunosorbent assay. 3. After surgery, a significant decrease in p-FN levels and a significant increase in EDA + FN levels was observed in all patient group compared with pre-operative levels. The duration of increased EDA + FN levels, but not p-FN levels, in group A patients was significantly longer than in group B patients. Although changes in p-FN levels between patients with and without liver cirrhosis were significantly different, there were no significant differences in the EDA + FN levels between these two patient groups. 4. In conclusions, EDA + FN and p-FN levels were found to exhibit opposite responses to surgical stress. Furthermore, with greater surgical stress, greater increases in EDA + FN levels were seen. The presence of liver cirrhosis had no significant effect on EDA + FN levels during the perioperative period; however, p-FN levels were significantly affected. 5. Thus, it is suggested that plasma EDA + FN levels reflect the magnitude of surgical stress more closely than do p-FN levels.