Health-related quality of life (HRQOL) is an important outcome factor in chronic diseases such as inflammatory bowel disease (IBD). This study used the Korean translation of the disease-specific, self-administered Inflammatory Bowel Disease Questionnaire (IBDQ) to compare HRQOL in ulcerative colitis (UC; n=98), Crohn's disease (CD; n = 49), and intestinal Behçet's disease (BD; n = 34). In addition to the current status, patients were asked retrospectively to recall their symptoms at the beginning and during the worst period of their disease. Disease activity was measured by St. Mark's Activity Index, Crohn's disease Activity Index (CDAI), and the Harvey-Bradshaw Index (HBI). In all IBD patients, including those with BD, the IBDQ total score during the worst period was significantly lower than that at present and that at the beginning of the disease. However, there were no significant differences between groups regarding the total IBDQ score or its various dimensions. In UC a strong correlation between IBDQ scores and St. Mark's Activity Index was observed (r = –0.708, P<0.001). IBDQ scores were also highly correlated with CDAI and HBI in both CD (r=–0.506, P<0.001 for CDAI; r = –0.600, P<0.001 for HBI) and BD (r = –0.687, P<0.001 for CDAI; r = –0.531, P<0.001 for HBI). However, the current IBDQ score was not related to demographic parameters such as gender, age, educational status, economic status, and marital status as well as disease factors such as duration of disease, history of operation or hospital admission, extent of disease in UC, involved region in CD, and clinical type in BD. We conclude that the Korean IBDQ is a responsive and promising instrument for measuring HRQOL of IBD patients in clinical trials. In addition, the IBDQ can be helpful in developing a disease-specific activity index in BD.