We report a case of idiopathic segmental ureteritis (ISU) in a 66-year old male. Upon receiving this case and all previous cases in the literature, we propose well defined clinically and pathological criteria for making the diagnosis of ISU. Exclusion criteria include: the presence of neoplasia, previous ureterial or renal surgery, calculous disease, tuberculosis, schistosomiasis, retroperitoneal fibrosis radiation and extrinsic compression. Inclusion criteria would require a preponderance of certain prominent clinical and pathological features such as; that 1) a discreet segment of involved ureter; 2) "creeping fat" of the ureter; 3) transmural chronic fibrosing inflammation; 4) mucosal ulceration; 5) marked underlying lympho-plasmacytic infiltrate with fibrosis and vascularization; 6) prominent lymphoid follicles with germinal centers presented in all levels of the ureteral wall and extending into peri-ureteral fat and 7) noncaseating granulomas. Of note, these features can also be seen in another idiopathic inflammatory disease such as Crohn?s disease.