The addition of a chiral hydrogen bonding additive, derived from N-acetyl-L-valine, to the non-aqueous mobile phase in silica gel liquid chromatography permits the chiral recognition of d- and l-amino acid derivatives as N-acetyl-O-tert-butyl esters. Chiral N-acetyl-L-valine-tert-butylamide is firmly adsorbed on the silica gel surface and forms the chiral hydrogen-bonded phase. The recognition process by which enantioselectivity is attained occurs predominantly in this de facto stationary phase. The main driving force for the recognition may be attributed to steric effects, exerted by the silica gel surface in adsorbing the solute—additive associates, rather than to the stability difference between the diastereomeric hydrogen-bonded associates as observable in solution.In contrast, the recognition process of chiral N-acetyl-L-valine-tert-butyl ester occurs predominantly in the bulk of the mobile phase. This additive, which shows retention on the silica gel similar to that of the solutes to be resolved, has little effect on recognition in the stationary phase process. The enantioselectivity should therefore be ascribed to stability differences between the diastereomeric hydrogen-bonded associates in the mobile phase.