DAMAGE ASSESSMENT & SUSTAINABLE CONSERVATION & MANAGEMENT OF EGYPTIAN ARCHAEOLOGICAL SITES AND BUILDINGS: EXPERIMENTAL AND APPLIED STUDY ON SAN EL-HAGAR " TANIS " – EGYPT This thesis addresses the subject of sustainable conservation and integrated management of archaeological sites and buildings through an applied study on the site of San el-Hagar (Tanis), one of the most prominent archaeological sites in the Egyptian Delta. The study aimed to analyze the current condition of the site, assess the deterioration phenomena, and develop a practical conservation plan that takes into account environmental, social, and cultural dimensions, with a focus on sustainability and community participation, The study began with an introduction that clarified the research problem and the objectives of the study, along with a critical review of previous studies, which enabled the researcher to identify important knowledge gaps. In the first chapter, the researcher focused on documenting the architectural and archaeological components of the Tanis site using accurate drawings prepared by the researcher, including temples, royal tombs, gates, and others. The deterioration phenomena and influencing factors were analyzed, highlighting the multiple values of the site (historical, archaeological, religious, architectural, and communal) as a foundation of the sustainable conservation approach, The second chapter provided a comprehensive assessment of the current condition of the site through an environmental, structural, and material analysis of the deterioration-causing factors, using precise scientific methods such as visual inspection and laboratory analyses of materials. This analysis underscored the importance of linking current problems to climatic, institutional, and social variables, The third chapter presented the theoretical and applied framework of the concept of "sustainable conservation", tracing the development of its theories and relevant international charters such as the Venice Charter and the Nara Charter. The researcher also addressed the current management reality of the Tanis site, pointing out a dysfunction in institutional coordination, a lack of specialized resources, and the marginalization of the local community's role. He called for adopting an approach that integrates environmental and social impact within conservation programs, In the fourth chapter, the researcher presented the applied study, which included a detailed conservation and management plan based on analytical tools such as SWOT analysis and hierarchical modeling of priorities. The plan included 3D digital documentation that reconstructs the site as it originally was, providing an important tool for archaeological interpretation, education, and community engagement, The main findings included: high rates of deterioration due to intertwined natural and human factors; the absence of a clear and sustainable conservation and management plan; the necessity of employing modern digital analysis and modeling tools; the importance of a flexible and participatory management model; and the potential for generalizing the plan to other Egyptian archaeological sites, The recommendations included: adopting the plan by the concerned authorities as a guiding model; developing the skills of professionals working in conservation and management; integrating the local community at all stages of the project; and enhancing collaboration between academics and executive bodies in policy-making. This study represents an important scientific contribution in the field of cultural heritage conservation in Egypt from a comprehensive and sustainable applied perspective.