Stable bleaching powder of international standard was manufactured by chlorination of properly slaked lime. Chlorine in 3-5% excess of calculated amount and slaked lime with 1-2% free moisture gave the standard product. The processing difficulties experienced were clogging of the hydration unit and ball formation in the chlorinator. Their causes were investigated. The effect of impurities in lime, temperature and moisture had been discussed. The shelf-life of stable bleaching powder had been studied.