Recent studies have found a relationship between the kidney and the intestinal microbiome, called the colo-renal axis. Mounting evidence suggests that patients suffering from chronic kidney disease (CKD) have an altered composition of gut microbiota. This leads to 1) the increased fermentation of intestinal proteins to uremic toxins such as p-cresyl sulphate and indoxyl sulphate, 2) an altered, more 'leaky' intestinal barrier, and 3) translocation of bacteria and toxins from the gut lumen to the circulation, inducing systemic inflammation. This may contribute to the increased morbidity and mortality in this population. Future studies are needed to confirm this hypothesis, and to assess whether manipulating the intestinal microbiota with pre-, pro-, or symbiotics may alter the development and course of CKD.