The aim of this study is prospectively to evaluate the serum C-reactive protein (CRP) and interleukin-6 (IL-6) levels in detection of acute appendicitis in patients with right iliac fossa pain. Data were collected in prospective manner on 102 consecutive patients with right iliac fossa pain. Laparotomy was performed for suspected acute appendicitis for 55 of the 102 patients, of whom 49 patients had appendicitis, 6 patients non-appendicitis (NA), and the other 47 patients had nonspecific abdominal pain (NSAP) and they did not undergo operation. Among those with appendicitis 31 had acute appendix (AA), 8 had gangrenous appendix (GA), and 10 had perforated appendix (PA). The WBC and CRP the mean (SEM) values were significantly different in AA, GA, and PA groups compared with NSAP and NA groups (P < 0.05). Although the mean IL-6 levels were significantly different only in PA group than the others groups (P < 0.05). The sensitivity and specificity of serum CRP measurements were calculated as 96% and 87%, respectively whereas these were 33% and 83% for IL-6 levels for the diagnosis of the acute appendicitis. As a result, measurement of the CRP levels and WBC have an additional diagnostic value on the diagnosis of the acute appendicitis but determination of IL-6 levels which added to the test combination of WBC and CRP, the sensitivity for the diagnosis of the acute appendicitis was not changed whereas the specificity was decreased to 66%.