Alum(KAl(SO_4)_2·12H_2O) is an inexpensive,efficient,non-toxic and mild catalyst for the one-pot synthesis ofα-aminophosphonates. A three component reaction of an aldehyde/ketone,an amine and triethyl phosphite was carried out under solvent-free conditions to afford the correspondingα-aminophosphonates in short reaction times and high yields with the green aspects by avoiding toxic catalysts and solvents. Alum (KAl (SO 4) 2 · 12H 2 O) is an inexpensive, efficient, non-toxic and mild catalyst for the one-pot synthesis of α-aminophosphonates. A three component reaction of an aldehyde / ketone, an amine and triethyl phosphite was carried out under solvent-free conditions to afford the corresponding alpha-aminophosphonates in short reaction times and high yields with the green aspects by avoiding toxic catalysts and solvents.