This paper will try to demonstrate that the presence in Italian system of design of both types of individual and collective learning (learning by doing and learning by using) generates a knowledge creation process based upon learning by interaction in which are involved both tacit and explicit design processes and actors. From this perspective social and cultural stock of competencies (locally materialized in territorial resources, actors' skills, community practices) increases through a situated process of interaction between actors. This process of interaction sets the development opportunities for design domain and in general the possible paths of innovation. All this can happen through a complex real time process of negotiation between interested actors; they make relevant decisions that individuate the path dependent trajectory of innovation. This fact from one side could reinforce the knowledge creation process within the specific design domain generating for example those cases of recursive learning we can identify in the Italian Industrial Districts system (and we could see this as a case of territorial lock-in), from another side a characteristic design openness from the point of view of the configuration of design resources. This confirms the hypothesis of an absorption capability of Italian system of design. Methods We have developed and tested (together with other members of SDI research) a new disciplinary methodology for the development of case studies in design area. Here we propose a theory based upon qualitative key factors pointed out from a number of case study of SDI research. Empirical base Our work is based upon the results of national research "Sistema Design Italia. Risorse progettuali e sistema economico. Il ruolo del disegno industriale per l'innovazione di prodotto. Sviluppo delle risorse progettuali del Sistema Italia tra risorse locali e mercati globali." funded by Ministero dell'Università e della Ricerca Scientifica e Tecnologica. This research has two different level of analysis:the first level focuses general maps of the Italian design system from the perspective of his productive articulation (through the lens of territorial localization and sectorial organization);the second level focuses a qualitative analysis of key innovation issues based upon the development of ad hoc case studies of design-driven product systems/firms