Objective . The acute onset of intense abdominal pain requires rapid evaluation, and since D-dimer level is reported to be useful in the diagnosis of patients with suspected acute superior mesenteric artery occlusion, our aim was to evaluate the value of D-dimer testing in the diagnosis of acute surgical abdomen with no precise diagnosis. Material and methods . Between July 2004 and June 2006, 93 patients with acute abdomen who required surgical exploration without precise diagnosis were admitted to this prospective clinical study. After surgery, the patients were divided into two groups: group 1 (n=52), patients who needed immediate laparotomy, and group 2 (n=41), patients without the need for laparotomy. Blood samples were taken to analyse D-dimer, white blood cell count and pH level. P-values of <0.05 were considered statistically significant. Results . There was a positive correlation between the plasma D-dimer level and leucocyte count. Leucocyte counts >16,800/mm(3) (p<0.01) and D-dimer levels >4.7 mu g FEU/mL were more sensitive (p<0.001). Sensitivity was 97.6 % and specificity 61.5 % for D-dimer level, and 82.9 % and 42.3 %, respectively, for leucocyte count. Metabolic acidosis at admission was the most important factor for mortality (p<0.001). Conclusions . In a patient with acute abdomen without precise diagnosis, a D-dimer level above the cut-off value (4.7 mu g fibrinogen equivalent units/mL) may be an indicator with high sensitivity for surgical pathology requiring laparotomy.