This dissertation aims at developing a model for planning process, based on concepts of adaptative planning, which integrate elements of total quality philosophy and sociotechnical systems, appropriate for small and medium size companies. From a theorical basis, the relationship between these three approaches are analized. A case study, covering two companies of the sizes here considered, was conducted, in order to identify the relevant pratical aspects of na effective planning system at this level. The proposed model was developed with the following characteristics: flexibility, simplicity and continuity, with the objective of providing the organizations that may adopt it with the proprieties of adaptation, integration and coordination, here identified, both at theorical and applied levels, as necessary to ensure na effective planning process.