The Andalusian Housing and Rehabilitation Plan, as a framework for the municipal housing and land plans, points towards the activation of housing and vacant land as one of the priorities of housing policy. Andalusian towns such as Bormujos or Bollullos de la Mitacion (Seville), with unfinished suburban projects, property developments and unfinished or empty housing, face the challenge of answering the demands of access to housing of citizens through the support of actions to use this vacant stock. To this end, the draft phase of plans for housing of both municipalities involves the development of a participatory process to ensure consensus between institutional and social actors and design lines of action on different situations of identified vacancies. The purpose of this paper is to extract key factors from this participatory process through the study of comparative cases and tools of Participatory-Action-Research. Based on the results obtained we define the main conclusions of this research to determine how a participatory process contributes to the design of activation strategies of empty housing and vacant land at municipal level.