beta-(1-Chloro-2-naphthyl)alanine and beta-(1-bromo-2-naphthyl) alanine were synthesized by ammonolysis of the corresponding alpha, 1-dihalo-2-naphthalenepropanoic acids derived from 1-nitro-2-naphthylamine by diazotization and condensation with acrylic acid in the presence of cuprous halides. The two analogs as well as the previously reported beta-(2-naphthyl)alanine and beta-(1-naphthyl)alanine were studied as growth inhibitors of Escherichia coli 9723, Leuconostoc dextranicum 8086, and Lactobacillus plantarum 8014. In general, the chloro and bromo analogs were more effective than the unsubstituted naphthylalanines as growth inhibitors of the three microorganisms studied.