Companies operate in a competitive and changing environment requiring increasingly effective and efficient management strategies. Lean is a proven philosophy in the industrial sector having helped companies to adapt to rapid market changes; to economic, technical, and social complexities; and to customer needs. For this reason, companies in the service sector are adopting Lean to improve their service management and to achieve economic, social, and environmental sustainability. This paper presents a model which uses Lean tools to facilitate the introduction of Lean in the management of primary care centers. The results show the implementation of Lean improved primary care center management, achieved stated objectives, and demonstrated faster adaptation to environmental needs and changes. The Lean philosophy developed and applied in the primary care center proved useful at a professional level facilitating developmental changes and prompting lasting improvements by developing a sustainable work culture.