A freeze-protected concentrated solution of alkali metal hydroxide comprising (a) at least 46% by weight of alkali metal hydroxide wherein at least 80% by weight of the alkali metal hydroxide is sodium hydroxide and (b) no more than 1.5% by weight of an additive selected from the group consisting of sulfuric acid and its alkali metal salts, citric acid and its alkali metal salts, and triglyceride. The freeze-protected solution has a freeze point of 5° C. or less, and thus is able to withstand temperatures below the normal freeze points of concentrated alkali metal hydroxide solutions. A process to prepare of the freeze-protected solution comprises adding the additive to a concentrated alkali metal hydroxide solution.