© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim The esterified maltodextrins (EMs) are prepared by enzymatic esterification of maltodextrin DE of 16 with three fatty acids (C-10, C-12, and C-16). Three EMs are maltodextrin decanoate (DE16_D), maltodextrin laurate (DE16_L), and maltodextrin palmitate (DE16_P). Their surface-active properties and anti-microbial activities are investigated with various concentrations (0–20% (w/w)). All EMs exhibit surface activity that depends on the chain length of the fatty acid. The anti-microbial activities of EMs and native maltodextrin are evaluated against Escherichia coli, a Gram-negative bacterium, and Staphylococcus aureus a Gram-positive bacterium. DE16_L is the most effective at retarding E. coli growth. The minimum inhibitory concentration (MIC) of DE16_L is 5% (w/w). Cell numbers of E. coli tend to decrease as the concentration increases for native maltodextrin, DE16_D, and DE16_L. On the other hand, DE16_P enhances the available cells of E. coli and S. aureus as concentration increases. EMs and native maltodextrin do not clearly retard the growth of S. aureus. This investigation indicates that the chain length of the fatty acid and the concentration of EMs affects their anti-microbial ability.