Crystal-induced colitis, a rare complication of sevelamer therapy in Chronic Kidney Disease (CKD) patients, presents diagnostic challenges. We report a case of a 39-year-old man with severe lower gastrointestinal bleeding attributed to sevelamer-induced colonic ulcers. Despite initial suspicion of Crohn's disease, histopathological analysis revealed crystalline material suggestive of sevelamer-associated colitis. Discontinuation of sevelamer led to the cessation of bleeding and stabilization of the patient's condition. This case highlights the importance of considering medication-induced gastrointestinal complications in CKD patients.