Autonomy is a prime issue on robotics field and it is closely related to decision making. Last researches on decision making for social robots are focused on imitating humans’ mind for taking decisions. Following this approach, we propose a motivational system for decision making using internal (drives) and external stimuli for choosing the right action. Actions will be selected from a finite set of skills in order to keep robot’s needs within an acceptable range. We present how our motivational decision making is applied to a social robot showing an improvement in robot’s autonomy.