An orthogonal surface-chem. gradient composed of self-assembled monolayers on gold has been prepd. by successive, controlled immersions in orthogonal directions into dil. solns. of dodecanethiol and perfluorododecanethiol. The resulting two-component orthogonal gradient in surface coverage was backfilled with 11-mercaptoundecanol, leading to a two-directional, three-component surface-chem. gradient. Water and hexadecane show distinctly different wetting behaviors on the gradient surface because of the differences in the hydrophobic and oleophobic natures of the three different constituents. These results are correlated with the chem. compn. maps of the surface obtained by XPS. The homogeneity and the ordering of the self-assembled monolayer were investigated by dynamic water contact angle measurements and polarization-modulation IR reflection-absorption spectroscopy.