One of the most common activities of human beings is that of decision-making. Every person is constantly deciding on a wide variety of different subjects. We all know, from our particular experience, that there are good and bad decisions, so a natural question arises. Are there any rules or procedures for decision-making which “guarantee” that the final result is a “good” decision? So, further in this article, we are going to describe and analyze, those structural elements, which are important for a making-decision process, such as decision to be rational. Decider, the problem situation, the decisional objects, the multitude of decisional alternatives, decisional criterions, the consequences for each alternative, and de making choice are the structural elements which each decision-making process should encounter for its rationality.