Disclosed is a process for the preparation of a glucosamine acid addition salt from fructose and ammonia or an ammonia source such as an ammonium compound by contacting fructose and ammonia or an ammonia source in the presence of (i) a solvent comprising about 25 to 100 weight percent water and 75 to 0 weight percent of an inert, organic, water-miscible solvent at a .sup.W.sub.WpH or .sup.S.sub.WpH of about 1 to 6; or (ii) a solvent comprising about 75 to 100 weight percent of an inert, organic, water-miscible solvent and 0 to 25 weight percent water at a .sup.W.sub.WpH or .sup.S.sub.WpH of about 1 to 10. A mannosamine acid addition salt also is produced as a co-product of the process.