A simple, efficient, and general method has been developed for the one-pot synthesis of a-aminophosphonic esters, under solvent-free conditions, with the use of CaCl2 as a Lewis base catalyst. The esters were obtained under mild conditions and in high yield (80 to 96%) and purity. They were synthesized by the reaction of diethyl phosphite with a mixture of aldehydes and amines, in the presence of CaCl2, and under solvent-free conditions. Major advantages of this protocol are: high yields, inexpensive method, making use of a non-toxic catalyst and finally mild and solvent-free conditions.