Background: Colonic epithelial cells function as a physical barrier to luminal toxins and antigens and regulate the transport of fluid, nutrients and electrolytes to and from the gut lumen. Autophagy is an evolutionarily-conserved mechanism by which self-digestion of cellular proteins and organelles during periods of cellular stress can occur. The importance of autophagy in colonic epithelial cells in development of intestinal disorders, such as inflammatory bowel disease (IBD) and cancer, is becoming increasingly apparent. Bile acids are classically known for their roles in facilitating digestion and absorption of fats. However, they have more recently become appreciated as a family of intestinal hormones and are known to be important in the pathogenesis of colonic inflammation and cancer. However, the mechanisms underlying bile acid actions are still poorly understood, and their roles in regulating colonic epithelial autophagy are not yet known. Aim: The aim of this study was to investigate the effects of the common colonic bile acids, deoxycholic acid (DCA) and ursodeoxycholic acid (UDCA), on autophagy in colonic epithelial cells. Methods: T84 colonic adenocarcinoma cells were grown on 30 mm Millicell-HA inserts until they formed a polarized monolayer, mimicking the phenotype of native epithelial cells. Cells were then treated bilaterally with DCA (200 μM) or UDCA (500 μM) for 24h. Expression levels of LC3 protein, a reliable indicator of ongoing autophagy, were then investigated by western blotting. Results: In cells treated with DCA for 24 h, expression levels of LC3 protein were increased 444 ± 145% (n = 4; p < 0.05) compared to untreated control cells. In contrast, UDCA exerted a relatively weak effect on autophagy that was not significantly different from untreated controls (203 ± 62 %; n = 4). Conclusions: Our studies suggest that the composition of the colonic bile acid pool is likely to be important in regulating the extent of epithelial autophagy in the colon. Given the important roles that autophagy plays in regulating inflammatory responses and cell survival, these data are important for developing our understanding of the role that bile acids play in the pathogenesis such diseases. Future studies will focus on characterising the effects of bile acids on epithelial autophagy, with the hope that this will ultimately lead to the development of new approaches to treat intestinal diseases.