Abstract: A series of new β-peptido sulfonamides, related to the chemotactic tripeptide fMLF-OMe, has been synthesized. The examined 1a,b–7a,b models contain the achiral –HN–(CH2)2–SO2– taurine (Tau) residue or the chiral –HN–CH(nBu)–CH2–SO2– and –HN–CH(iBu)–CH2–SO2– residues, corresponding to the β-aminocarboxylic acid counterparts β3-HNle and β3-HLeu, respectively. The biological activity of the new analogues has been determined on human neutrophils and compared with that of the reference ligand as well as that of the previously studied related models. The results are analyzed in terms of structure–activity relationships. The conformational preferences of the new tripeptides 1b and 2b, containing a central chiral β-amino-ethanesulfonic acid residue, have also been discussed. [Copyright &y& Elsevier]