It was anticipated that the course of preexisting inflammatory bowel diseases (IBD) should improve after orthotropic liver transplantation (OLT). However, exacerbation of IBD or the development of de novo IBD after OLT was described despite sufficient allograft immunosuppressive therapy. Here we report a 13 years old boy who underwent liver transplant from deceased donor for cryptogenic liver cirrhosis. Five months after transplantation the patient presented with continuous diarrhea and abdominal protrusion. He received tacrolimus and mycophenolate mofetil as immuno­suppressive medications. General physical examination revealed a boy with stable vital sign and without fever. The only positive finding in physical examination was enlargement of the abdomen without tenderness. Laboratory tests showed alkaline phosphatase 2160 IU/L, total bilirubin 28.1 mg/dL and direct billirubin 13.5 mg/dL. Prothrombin time was 18 seconds and INR was 2.14. The patient underwent colonoscopy due to chronic diarrhea. Colonoscopy showed diffuse erythematous mucosa and multiple exudative ulcers and pseudopolyps with diffuse loss of vascularity. All of these were indicators of colitis. Histopathologic examination of colon biopsy was in favor of ulcerative colitis. The patient received mesalasine and prednisolone led to rapid clinical improvement that was confirmed by colonoscopy 5 weeks later showing a normal mucosa, with only mild inflammation on histopathologic examination of colon biopsy. The lesson we learned from this case is that when the patient developed chronic diarrhea after liver transplantation, IBD should be consider in differential diagnosis, and the patient should undergo colonoscopic examination.