Formation of β-arylaminoacrolein from β-ethoxyacrolein (I) and arylamine was studied kinetically. Hammett plot for second order rate constants gave a good linear line with ρ value of-2.63. Neither triethylamine nor acetic acid acted as an effective catalyst for the reaction. In the presence of acetic acid a remarkable amount of malonaldehyde dianil formed as a by-product. Reaction mechanism was discussed.