Background: Alzheimer’s disease (AD) negatively impacts patients’ ability to make advantageous decisions, i.e., a core ability contributing to the preservation of autonomy. Objective: The present study aims to analyze the changes that occur in the decision-making competence (DMC) in AD patients and to determine if these changes are related to the deterioration of executive functions and working memory. Method: To this end, 20 patients with AD and 20 elderly control adults were assessed using executive, working memory, and DMC tasks. The latter comprised the Iowa Gambling Task (IGT) and a scenarios task based on situations inspired by everyday life and performed under conditions of risk and ambiguity. Results: Results revealed lower performances in AD patients than in elderly control adults for all the tasks assessing cognitive functions. The AD patients also made more strategy changes during the IGT. In the scenarios tasks, the two groups took as many ambiguous or risky decisions, but AD patients tended to take more risks in the context of gain than elderly control adults did. Switching and updating ability, as well as working memory, appeared to be involved in decisions in tasks inspired by everyday life, while inhibition was more related to the IGT performances. Conclusion: Working memory and executive functions seem to be involved in decision-making, but in different ways in gambling and daily-life situations.