The voltage-gated K+ channel Kv1.5 is expressed in cardiac myocytes, where it is important during repolarization of the atrial action potential. N-cadherin is an adhesion molecule mediating homophilic cell-cell contacts in cardiomyocytes and is essential for cardiac development. N-cadherin has previously been shown to regulate N-type voltage-gated Ca2+ channel activity. Since Kv1.5 is localised in intercalated disks in proximity to N-cadherin we aimed to investigate the role of N-cadherin in Kv1.5 regulation. cRNA coding for Kv1.5 and for N-cadherin was injected into Xenopus oocytes and Kv1.5 channel activity analysed by dual electrode voltage clamp. Kv channel activity was observed in oocytes expressing Kv1.5 but not in water injected oocytes. The coexpression of N-cadherin significantly increased Kv1.5 channel activity by a factor of 2-3, but did not appreciably modify channel activation properties. The results demonstrate that N-cadherin enhances Kv1.5 activity without altering channel kinetics, an effect presumably affecting repolarization of atrial cardiac myocytes.