AIM:To evaluate the incidence and risk factors of Korean tuberculosis(TB) infection in patients with inflammatory bowel disease(IBD) undergoing anti-TNF treatment.METHODS:The data of IBD patients treated with anti-TNFs in 13 tertiary referral hospitals located in the southeastern region of Korea were collected retrospectively.They failed to show response or were intolerant to conventional treatments,including steroids or immunomodulators.Screening measures for latent TB infection(LTBI)and the incidence and risk factors ofactive TB infection after treatment with anti-TNFs were identified.RESULTS:Overall,376 IBD patients treated with antiTNF agents were recruited(male 255,mean age of anti-TNF therapy 32.5±13.0 years);277 had Crohn’s disease,99 had ulcerative colitis,294 used infliximab,and 82 used adalimumab.Before anti-TNF treatment,screening tests for LTBI including an interferon gamma release assay or a tuberculin skin test were performed in 82.2%of patients.Thirty patients(8%)had LTBI.Sixteen cases of active TB infection including one TB-related mortality occurred during 801 personyears(PY)follow-up(1997.4 cases per 100000 PY)after anti-TNF treatment.LTBI(OR=5.76,95%CI:1.57-21.20,P=0.008)and WBC count<5000 mm3(OR=4.5,95%CI:1.51-13.44,P=0.007)during follow-up were identified as independently associated risk factors.CONCLUSION:Anti-TNFs significantly increase the risk of TB infection in Korean patients with IBD.The considerable burden of TB and marked immunosuppression might be attributed to this risk.