Foamed two-part hard surface treatment composition which is formed by the admixture of two aqueous compositions, particularly (a) an aqueous alkaline composition comprising a bleach constituent, with (b) an aqueous acidic composition comprising a peroxide constituent, which compositions are kept separate, but which are admixed immediately prior to use or upon use to form a foamed hard surface treatment composition. The foamed two-part hard surface treatment composition are particularly useful in the cleaning of hard surfaces. Preferred foamed two-part hard surface treatment composition provide both a cleaning and sanitizing or disinfecting benefit to hard surfaces, while releasing little or no free chlorine gas to the ambient air.