This paper reports on the use of a scanning force microscope (SFM) for the tip-assisted base hydrolysis of an ester-terminated alkanethiolate monolayer on Au(111). We have found that contact imaging accelerates the base hydrolysis of a dithiobis(succinimido undecanoate) monolayer relative to the surrounding unimaged area. It is proposed that (1) the mechanical disruption by the SFM probe tip of the steric barrier imposed by the neighboring adsorbates facilitates access of hydroxide ions to the buried acyl carbons in the adlayer, and (2) the surface area hydrolytically transformed by this disruption can be controlled by the SFM imaging conditions, Findings in support of our conclusions are presented, and potential implications to nanotechnology are briefly discussed.