Alkaline hydrolysis of N,N-disubstituted О,О-dialkyl (aminomethyl)phosphonates gives rise to the corresponding О-alkyl (aminomethyl)phosphonic acids. The reaction of potassium О-alkyl (aminomethyl)-phosphonates with organyl halides involves quaternization of the nitrogen atom to form dipolar aminophosphoryl compounds, aminophosphabetaines.