The present invention describes a solid calcium hypochlorite composition comprising calcium hypochlorite and about 0.5% to about 50% by weight of substantially water-insoluble and unchlorinated magnesium compounds, said magnesium compounds being derived from impure hydrated lime. Furthermore, the present invention describes a process for making this composition, which is an improvement in the known process for the manufacture of a solid calcium hypochlorite composition wherein an aqueous slurry comprising a hydrated lime, a mixture of hydrated lime and at least one alkali metal hydroxide, or a mixture of hydrated lime and at least one alkali metal hypochlorite, is chlorinated to form an aqueous chlorinated slurry containing calcium hypochlorite and further processing said chlorinated slurry to recover a solid calcium hypochlorite composition.