UT-B1 has been localized to bladder and ureter in both rat and mouse (1,2). Recently UT-B1 has been localized to bladder urothelium in humans (3), while its expression and localisation in human ureter have not yet been reported. In this study, Western blotting of normal human ureter whole homogenate protein was performed. Immunoperoxidase staining was performed using 4μm formalin-fixed, paraffin-embedded normal human ureter tissue sections. Both methods employed a well-characterized hUT-B c19 antibody. A characteristic 40-45kDa band equating to glycosylated UT-B1 was detected in human ureter whole homogenate protein. Treatment with PNGaseF gave a discrete 30kDa band as previously reported for human bladder tissue. This signal was completely ablated in de-glycosylated protein probed with primary antibody incubated with the immunizing peptide. In control experiments strong peroxidase staining was evident in human bladder urothelium. In contrast, minimal peroxidase staining, localized to the basal cell layer, was detected within ureter urothelium. Some strong staining was detected in sub-epithelial blood vessels of the ureter tissue. UT-B1 expression and localisation in human ureter urothelium differs markedly from that of human bladder urothelium. This may be reflective of the separate embryological lineages of each tissue and the varied efflux kinetics associated with the differing functional roles of each tissue. Further research is now required to investigate whether ureteral UT-B1 may be subject to more acute regulation.