(57) A detergent composition containing a stabilized active halogen source is disclosed. An active halogen source, such as a hypochlorite, in aqueous solution, is stabilized by combining it with anhydrous or partially anydrous builders, as well as fillers, defoamers, polyelectrolytes, and hydroxides to form a solid detergent composition. Preferably, the aqueous solution of the active halogen source is first combined with at least one sulfonamide. It is found that inclusion of the sulfonamide further improves stability, particularly at higher temperatures and permits the active halogen source to be stabilized as a slurry. The destaining activity of the halogen remains effective even after a prolonged storage period.