The presence of a bladder mass in a patient with inflammatory bowel disease poses a diagnostic dilemma. We present the case of a 26‐year‐old male with a bladder mass who had not previously been diagnosed with Crohn′s disease. Initial biopsies of the bladder mass were consistent with inflammatory changes, but superficial transitional cell carcinoma could not be reliably excluded. Subsequent evaluation confirmed the presence of Crohn′s disease with bladder involvement, and the patient underwent bowel resection and partial cystectomy. Pathologic evaluation demonstrated Crohn’s disease and no evidence of malignancy. Accurate differentiation of benign and malignant bladder masses in patients with inflammatory bowel disease may be difficult and requires cooperation between pathologists and clinicians.