This study was investigated about the effect of glibenclamide (GLY) which is K^+ channel blocker on renal function in rabbit, GLY, when given into the vein, produced the diuretic action accompanied with the increases of amounts of Na^+ and K^+ excreted into urine (E_(Na), E_K), and then osmolar and negative free water clearances (C_(osm), `T^c_(H2O)), fraction excretory rates of filtered Na^+ and K^+ (F_(Na), F_K) and ratios of E_K against E_(Na) were augmented. Filtration fraction (FF) were reduced because renal plasma flow (RPF) were not changed but glomerular filtration rates (GFR) were diminished. GLY administered into a renal artery exhibited significant reduction of urine volume along with the decreases of GFR and RPF in only experimented kidney whereas changes of renal function was not observed in control kidney. GLY given intracerebroventricularly exhibited diuretic action along with the increase of E_(Na), E_K and F_(Na), F_K by small dose which was not affect on renal function when it given into the vein. Above results suggest that GLY given into the vein in rabbit produce the diuretic action by inhibition of electrolytes reabsorption in renal tubules through central function.