The symbiotic relationship that exists between humans and their intestinal bacteria is crucial in maintaining our gastrointestinal health. Growth of bacterial populations in the human colon is enhanced by the provision of nitrogen, in the form of urea, via colonic urea transporters (1). Our previous studies have identified two distinct urea transporters within the human colon, namely UT-B1 (2) and UT-A6 (3). The aim of the present study was to investigate the expression of these two transporters along the length of the human gastrointestinal tract. Using purchased cDNA samples (AMS Biotechnology,UK), initial PCR experiments surprisingly showed that both UT-B1 (colon > small intestine > stomach) and UT-A6 (stomach = small intestine = colon) were expressed at the RNA level throughout the gastrointestinal tract. Next, western analysis was performed using protein samples produced from gastrointestinal tissues obtained with patient consent at surgical resection procedures. Using the characterised BUTB-PAN antibody (2), experiments confirmed the now expected abundance pattern for the 35 kDa UT-B1 protein signal (i.e. colon > small intestine > stomach). Finally, western analysis was also performed using the hUT-A6#C antibody, raised to the unique C-terminal of UT-A6. This novel antibody successfully detected a 23 kDa signal, corresponding to the predicted size for UT-A6 protein, within colonic plasma membrane-enriched protein samples. This study shows that urea transporters are expressed all along the human gastrointestinal tract, and not just in the colon as predicted. It is also the first study to detect UT-A6 at the protein level. These findings suggest that urea transport mechanisms within the human gastrointestinal tract are more extensive than previously proposed.