Background: Vitamin D deficiency is commonly seen in patients with inflammatory bowel disease (IBD). Vitamin D deficiency in IBD patients with ileostomy has not been systemically studied. The aim of the study was to assess the frequency and risk factors associated with low 25(OH) D3 levels in those patients. Methods: 112 eligible IBD patients with ileostomy were studied. Demographic, clinical, and endoscopic variables were analyzed. Vitamin D levels before and after ileostomy were compared when available. Levels of serum 25(OH)D3