Molecules of 2-mercaptoethanol (ME) were spontaneously chemisorbed on silver, copper, and gold surfaces. Surface-enhanced Raman scattering investigation revealed that, as for unsubstituted alkanethiols, the average orientation of the "molecular chain" of ME is the most perpendicular to the metal surface for ME molecules adsorbed on silver. Immersion of an ME-modified electrode in diluted ME solution leads to quick desorption of a portion of the monolayer and an increase in the relative surface concentration of the gauche conformer. The time constant of this rearrangement (below 1 min) is more than 1 order of magnitude shorter than that of monolayers formed from analogous thiols (HS-(CH2)(2)-X) with X = CH3, NH2, COOH, or SO3Na. The structure of the ME monolayer is highly pH-sensitive, but it is independent of the presence of neutral salts in solutions. In acidic solutions, the surface concentration of a gauche conformer considerably increases. Since protonation of a significant number of hydroxyl groups is unlikely under the conditions used, it is likely that in acidic solutions the kinetics of the desorption and the desorption/adsorption equilibrium are changed. It is probable that desorption of ME as thiol molecules is facilitated because some of the sulfur atoms of ME adsorbed as thiolate are protonated. We also found an analogous effect, although less pronounced, for monolayers self-assembled from propanethiol. This indicates that this mechanism, so far not considered, can also be important for some other (especially short-chain) thiols. In basic solutions, the concentration of a trans conformer increases and probably some of the hydroxyl groups dissociate. For all investigated solutions, the structure of the ME monolayer on gold was found to be less affected by its surroundings than that of monolayers on silver or copper.