Previous studies have documented the expression of four kinetically-distinct voltage-gated K⁺(Kv) currents, I_to,f, I_to,s, I_K,slow and I_ss, in mouse ventricular myocytes and demonstrated that I_to,f and I_to,s are differentially expressed in the left ventricular apex and the interventricular septum. The experiments here were undertaken to test the hypothesis that there are further regional differences in the expression of Kv currents or the Kv subunits (Kv4.2, Kv4.3, KChIP2, Kv1.5, Kv2.1) encoding these currents in adult male and female (C57BL6) mouse ventricles. Whole-cell voltage-clamp recordings revealed that mean (± SEM) peak outward K⁺ current and I_to,f densities are significantly (P < .001) higher in cells isolated from the right (RV), than the left (LV), ventricles. Within the LV, peak outward K⁺ current and I_to,f densities are significantly (P < .05) higher in cells from the apex than the base. In addition, I_to,f and I_K,slow densities are lower in cells isolated from the endocardial (ENDO), than the epicardial (EPI), surface of the LV wall. Importantly, similar to LV apex cells, I_to,s is not detected in RV, LV base, LV EPI or LV ENDO myocytes. No measurable differences in K⁺ current densities or properties are evident in RV or LV cells from adult male and female mice, although I_to,f, I_to,s, I_K,slow and I_ss densities are significantly (P < .01) higher, and APD₅₀ are significantly (P < .05) shorter in male septum cells. Western blot analysis revealed that the expression levels of Kv4.2, Kv4.3, KChIP2, Kv1.5 and Kv2.1 are similar in male and female ventricles. In addition, consistent with the similarities in repolarizing Kv current densities, no measurable differences in ECG parameters, including QT_c intervals, are detected in telemetric recordings from adult male and female (C57BL6) mice.