The intestinal epithelial lining is constantly renewed every 2-5 days1. The efficient restitution of this barrier is essential to maintain its functional integrity which can be severely compromised during pathologies such as cancer, inflammatory bowel disease or diarrhoea2. Growing evidence indicates that K+ channels are key regulators of the epithelial repair process3, however, involvement of the KCNQ1 K+ channel in colon repair has never been investigated to date. The aim of this study was to evaluate the involvement of KCNQ1 in modulating the integrity of the epithelial barrier in colorectal cancer (CRC) cells. DLD-1 and HT29cl.19A cell lines were used in this study, which are representative of intermediate and well-differentiated CRC phenotype, respectively. Both cell lines have an active β-catenin:TCF4 signaling complex which regulates expression of KCNQ1. Wound healing (closure of the epithelial monolayer after scoring with a sharp needle) and migration assays were used to study the repairing ability of the epithelial cells at 24h and 48h following the inhibition or activation of the β-catenin:TCF4 signaling complex. The glycogen synthase kinase 3-β inhibitor (GSK3-iX) increased β-catenin activity and inhibited KCNQ1 expression. This resulted in a decreased repair rate after injury and also delayed cell migration which was associated with increased N-cadherin expression. By contrast, transfection with a dominant negative TCF4 (hΔN-TCF4), reduced the transcriptional activity of the TCF4 complex and enhance the expression of KCNQ1. This led to a more rapid repair rate following injury accompanied by enhanced cell migration. Investigation of the short-circuit current (Isc) across HT29cl.19A monolayers revealed that 24h treatment with GSK3-iX decreased the forskolin-stimulated KCNQ1 currents with no significant effects on the calcium-activated intermediate conductance IK1 (KCNN4) currents when stimulated by carbachol. Thus, the decreased Isc current observed in response to GSK3-iX treatment was specific to KCNQ1. To further establish the specific role of KCNQ1 in epithelial barrier restoration, SiRNA knockdown of KCNQ1 (sQ1) and two specific KCNQ1 channel blockers, chromanol 293B and HMR 1556 were used in HT29cl.19A cells. Silencing of KCNQ1 expression resulted in a decrease in wound closure rate 24h after injury compared to non-transfected HT29cl.19A cells. Inhibition of KCNQ1 activity by channel blockers resulted in a decreased rate of wound closure 24h post-injury. Taken together these results indicate that both KCNQ1 protein expression and its channel function are essential for colonic epithelial repair. We propose KCNQ1 as a novel therapeutic target in restoring colonic epithelial barrier function in cancer or inflammation injury.