Abstract: The present invention relates to stable and highly purified stable hydralazine hydrochloride compositions and stable hydralazine-containing pharmaceutical compositions. A sterile aqueous injectable pharmaceutical composition suitable for parenteral administration is described comprising a therapeutically effective dose of hydralazine hydrochloride in a pharmaceutically acceptable carrier or diluent wherein the hydralazine hydrochloride is essentially free of phthalazines, hydrazine and metal ions. In addition, a stable sterile aqueous pharmaceutical composition comprising hydralazine hydrochloride in a pharmaceutically acceptable salt or diluent is described that is colorless and has no visible particulate matter.