We report a case of simultaneous occurrence of inflammatory bowel disease (IBD) and Graves' disease. A review of reported cases of simultaneous onset of ulcerative colitis (UC) and autoimmune hyperthyroidism is presented. A discussion of the prevalence of thyroid disease in patients with UC and possible common autoimmune etiology is entertained. The concurrent presentation has implications for the diagnosis and treatment of both diseases. At the time of suspected initial presentation or exacerbation or preexisting IBD, we emphasize the need to consider both IBD and thyroid disease in the differential diagnosis for optimal patient management.