In this paper we demonstrate that self-assembled monolayers (SAMs) of alkanethiols on gold can be used as effective photoresists. UV photolysis of analkanethiol SAM generates the corresponding sulfonate in the monolayer film. The sulfonate is easily rinsed off of the surface with water, exposing a clean gold substrate, which can then be modified with subsequent chemistry. We describe here experiments in which an alkanethiol SAM on a gold film on silicon is irradiated through a mask, followed by immersion of the sample in an aqueous acid etching solution (HCl:HNO3:H2O = 3:1:4). The gold is etched away from the areas which have been exposed to UV radiation leaving a pattern which reproduces the original mask. The spatial resolution in the present experiments is limited by the mask which is a 6-mum wire grid. Scanning electron microscopy images of patterned samples show sharp edges to the features suggesting that spatial patterning on the 1-mum scale should be attainable with this simple chemistry.