The agenda effect refers to the ability of media to influence the public perception of reality, from the mental perspective, thus amplifying the importance of issues by providing news and repeatedly placing them in a certain order on the media agenda. The general formula of the agenda effect involves several key concepts, such as: awareness, prominent, priority. Notifying chronologically the main stages in the development of concepts and that are related with the agenda effect, it is evident that the particular operating characteristics and its focus are: a) the ability to influence public media from the perspective of mental perception of reality, b) the certainties and probabilities on the achievement of a goal through information during the election campaigns. The constant attention paid by researchers from various fields (sociology, psychology, political science) to this effect confirms the importance of the subject. Also, in present times, the importance is determined by: the pluralism-way of the communication, the industrialization process of communication and the media globalization.