Antimicrobial peptides and their mimetics offer a potential new disinfective tool. beta-Peptoids (oligo-N-substituted beta-alanines) were synthesized and investigated for antimicrobial activity. A block approach whereby di- and tri-beta-peptoids were first prepared and then ligated via amide bond formation to synthesize larger beta-peptoids was developed. The beta-peptoids were found to possess moderate activity in an Escheridchia coli assay.