A 23-year-old woman was admitted in November, 2002, complaining pain of the left side and buttock. She had ulcerative colitis when she was 16 and received medical treatment. Based on physical examination and findings of magnetic resonance imaging and bone scintigrapy, as sacroiliitis complicated by ulcerative colitis. was diagnosed Reports on sacroiliitis and ankylosing spondylitis complicated by inflammatory bowel diseases (IBD) are relatively rare in Japan, whereas they are common complications of IBD in Western countries. The efficacy of steroids on pain relief of sacroiliitis and ankylosing spondylitis is unclear.