Abstract: This invention relates to a pharmaceutical composition comprising sparfloxacin and a stable aqueous solution of sparfloxacin of the formula (I): ##STR1## comprising sparfloxacin, one or more polyhydroxymonocarboxylic acids, or lactone derivatives thereof, at least in a stoichiometric quantity with respect to sparfloxacin, and, optionally, an excess of said polyhydroxymonocarboxylic acid or another pharmaceutically acceptable acid for ensuring full solubilization of the salt so formed, not exceeding 5, and optionally an isotonic agent and/or other pharmaceutically acceptable additives.