The reactions of adamantanethione (1) with several Grignard reagents (MeMgCl, n-BuMgCl, and t-BuMgCl) have been investigated. In contrast to analogous reactions with ketones, there is no evidence of addition to the CS carbon of 1. Rather, reaction of 1 with n-BuMgCl or t-BuMgCl affords 2-adamantanethiol as the major product along with minor amounts of sulfides and an episulfide. Reactions of 1 with MeMgCl are very slow and afford a variety of products as a result of secondary reactions.