Abstract Using p-acetamidophenol as an active hydrogen component, two Mannich bases: N,N-[(5-acatamido-2-hydroxy)benzyl]ethylamine(I) and N-[(5-acatamido-2-hydroxy)benzyl]ethylamine(II) were synthesized via a general synthesis protocol. .The structures of the target molecules were elucidated by a combination of spectral techniques (UV, IR, 1H NMR and MS). The Mannich bases were evaluated for their antimicrobial activity against seven standard human pathogens. Compounds I and II showed excellent activity against Escherichia coli at 10 and 20mg/ml. Furthermore, compound II showed excellent activity against all test organisms at 20mg/ml. Both compounds exhibited significant antifungal activity at test concentrations.