We investigated the cognitive mechanisms underlying change in implicit cognitions following exposure to alcohol portrayals. More precisely, we tested in an experimental study whether this change depends on controlled or automatic processes by putting participants in a state of self-regulatory fatigue prior to being exposed to alcohol portrayals. Ninety participants were randomly assigned to a 2 (attitude measure: before vs after) × 2 (alcohol portrayal: yes vs no) × 2 (ego depletion: yes vs no) mixed design to assess whether the effects of alcohol portrayals affected cognitive resources. It was hypothesized that alcohol portrayals would have more of an impact on participants submitted to an ego-depletion task. We found a change in attitudes toward alcohol only for participants that had been exposed to alcohol portrayals, and who had not been cognitively depleted. These results suggest that these changes rely on controlled, resource-dependent processes rather than on purely associative and automatic processes. Implications regarding alcohol advertising effects on public health are discussed.