The sustainability of 129 small ruminant farming systems in Lebanon and 100 in Algeria was analysed on the basis of the quantitative multi-criteria method IDEA (Indicateurs de Durabilité des Exploitations Agricoles, or Farm Sustainability Indicators). Forty-one indicators covering the agro-ecological (including biodiversity, land management, agricultural practices), socio-territorial (product quality, employment and services, ethics and human development) and economical (viability, independency, transmissibility and efficiency) dimensions of sustainability were considered and applied in different contexts: sedentary, semi-transhumant, transhumant, semi-nomad or nomad production systems. Some indicators of the original method were inadequate in these systems, other were reformulated on the basis of appropriate references. In a semi-arid and pastoral context, the stocking rate, soil fertilisation, or nitrogen balance are examples for which more specific information is needed. The relative weighting of indicators deserves also attention. This methodological approach allowed identifying different categories of systems according to the three dimensions of sustainability. Global scores of sustainability were attributed to the more diversified systems such as the sedentary or horizontal transhumant ones. This method can be used to generate decision support tools and to model the sustainability of livestock farming system.