The aim of this study was to prospectively evaluate the correlation between clinical scoring systems and C-reactive protein (CRP) in inflammatory bowel disease. The modified Harvey-Bradshaw index was used in 40 patients (58 assessments) with Crohn's disease, and the Lichtiger score in 29 patients (36 assessments) with ulcerative colitis. In ulcerative colitis, CRP was elevated in 14%, 42%, 64%, and 83%, respectively, of subjects with quiescent, mild, moderate, and severe disease. There was a linear correlation of log(CRP) with clinical score except for proctitis. In Crohn's disease, CRP was elevated in 54%, 70%, 75%, and 100%, respectively, of subjects with quiescent, mild, moderate, and severe disease. We conclude that the clinical score has a good correlation with CRP in ulcerative colitis except for proctitis, whereas clinical score has a poor correlation with CRP in Crohn's disease, particularly in those with clinically quiescent, fibrostenotic, and ileal disease.