CT scanning allows assessment of airway-wall thickness and is useful for diagnosing and assessing various lung diseases, including asthma and COPD. Several studies have reported that CT scan-estimated dimensions are positively correlated with pulmonary function test results and a positive response to treatment. However, to our knowledge, airway disease complicated by inflammatory bowel disease has not yet been assessed using CT scan-estimated dimensions. A 61-year-old woman with ulcerative colitis (UC) complained of cough, sputum, and fever 4 months after undergoing a total colectomy and rectal mucosectomy. Examination of bronchial biopsy samples demonstrated lymphocytic and plasma cell infiltration of the epithelium and submucosa. CT scan-estimated dimensions indicated thickening of the airways. Chronic bronchitis complicated with UC was diagnosed, and high-dose inhaled corticosteroid therapy was prescribed. Three months later, the CT scan-estimated dimensions of the patient’s airways, her symptoms, and pulmonary function test results were dramatically improved.