New chiral receptors characterized by acyclic polyether skeletons and neutral terminal substituents were derived from naturally occurring monensin, lasalocid, salinomycin and nigericin ionophores. Their chiral recognition ability was investigated by ion-selective electrode and1H-NMR spectroscopic methods. Monensin ester and amide derivatives specifically formed 1:1 complexes with chiral amine salts and exhibited excellent enantiomer selectivity, while parent monensin rarely discriminated between the enantiomers of examined amine salts. This review describes how chemical modification of naturally occurring ionophores provides unique molecular recognition functions and a new synthetic strategy for chiral receptor molecules.