Conventional gene targeting is a powerful tool to study the influence of specific genes on behavior. However, conclusions relevant for adult animals are limited by consequences of gene loss during development. Mice lacking protein kinase C ε (PKCε) consume less alcohol and show greater acute sensitivity to alcohol than do wild-type mice. There are no selective inhibitors of PKCε that can be administered systemically and cross the blood–brain barrier to test whether these phenotypes result from loss of PKCε during development or in adulthood. Here we used conditional expression of PKCε in the basal forebrain, amygdala, and cerebellum to rescue wild-type responses to alcohol in adult PKCε^−/− mice. Subsequent suppression of transgenic PKCε restoredPKCε^−/− behaviors. These findings establish that PKCε signaling in the adult brain regulates alcohol consumption and sensitivity. If this extends to humans, then PKCε inhibitors might prove useful as novel therapeutics for alcoholism.