The aim of this study was the evaluation of diuretic potential of Delphinium brunonianum. Acute diuretic effect in rats was evaluated 8 h after administration of various doses of crude extract, fractions and hydrochlorthiazide. While, prolonged effect of butanolic fraction was assessed after 7days of oral administration in rats. Thereafter, involvement of different pathways in diuretic activity was also appraised. Furthermore, polyphenolic contents in butanolic fraction were assessed using HPLC/UV-VIS technique. All doses of extract and fractions induced a prominent increase in urine and Na+ excretion with no effect on excretion of K+. Prior administration of indomethacin and atropine considerably avoided the diuretic effect of butanolic fraction. Regarding the quantitative chemical analysis the polyphenolic contents were recorded as 28.78 µg/mg. Thus results of present investigation suggested that Delphinium brunonianum possess remarkable diuretic potential.