The enantiomers of 17 α-hydroxybenzylphosphonate diethylesters containing para, or ortho substituents or other aromatic rings (1-naphthyl, 2-naphthyl, and 2-thienyl) have been successfully separated by HPLC on a Whelk-O 1 chiral stationary phase which is superior to other CSPs. The effect of the substituents, particularly halogens, on the enantioselectivity was investigated and related to a chiral recognition model. The absolute configurations of 4-methyl and 2-methyl substituted α-hydroxybenzylphosphonates were obtained by measurement of the circular dichroism spectra of the isolated enantiomers. Chirality 10:100–105, 1998. © 1998 Wiley-Liss,Inc.