Ulcerative colitis is an inflammatory bowel disease. Opposite to Crohn's disease, it affects only the mucosa and submucosa of the large intestine. The disease can have episodes of flares and remissions. Endoscopy studies often disclose pseudopolyps, which are perceived as non-neoplastic and usually do not require removal. Rarely pseudopolyps can become big or even gigantic, leading to abdominal pain, bowel movement dysfunction, or even bowel obstruction. We present a case of a 37-year-old male patient with ulcerative colitis who was operated on because of a gigantic pseudopolyp causing bowel obstruction.