Abstract: The present invention is directed to a composition in solution (often, an aqueous solution) which comprises a combination of molecular iodine (I2) and an acceptable source of iodate (IO3), and an acid (inorganic or organic), wherein iodide and iodate are present in the composition at a molar ratio of about 0.1 to about 25, the concentration of uncomplexed molecular iodine is a disinfectant, biocidal and/or antimicrobial (depending upon the end use of the composition) effective amount the concentration of acid in the composition is effective to provide a buffering pH in the composition ranging from about 1.5 to about 6.5. Compositions according to the present invention are storage stable for unexpectedly long periods of time (up to about 5 years), and find use as dis infecting solutions, as germicides and/or biocides (e.g. antiviral, antibacterial, antifungal, antispore etc.