This study focuses on the meanings of advocacy and lobby as well as how these activities are performed in Brazil and the United States. By considering different contexts and historical developments, we analyze the activities of three civil society organizations to understand how they operate as legitimate groups whose advocacy activities expand the concept of democratic representation. The study concludes that advocacy fosters a deliberative type of democracy, which presumes that citizens have the right to participate in public discussion and deliberation. The study indicates that different stages of advocacy and lobbying processes, the influence of regulatory framework, the difficulties to act in coalition due to ideological differences, and members' private interests shape the main characteristics of civil society organizations' (CSOs) advocacy policies.