One of the approaches to achieve sustainable development is based on smart specialization. Rural areas are of particular importance in ensuring sustainable development, the smart development of which largely determines the balanced sustainable development of a state as a whole. The present study reflects the quantitative and the qualitative assessment of sustainable development in the region of Latgale (Latvia) on the level of 19 districts; the assessment has been carried out on the basis of the concept of smart specialization. The assessment has been performed within the framework of the project 5.2 of the National Research Programme EKOSOC-LV. The quantitative assessment is based on scientific and practical experience taking into consideration the distinguishing features of the development of Latvian regions and districts, and it has resulted in the establishment of an integrated index (Smart Development Index), which comprises four dimensions ñ Resources, Population, Economy, and Management. The qualitative assessment is based on the views concerning the cornerstones of smart specialization and the factors influencing it expressed by experts from the state administration, business and scientific environment. Expert opinions have been collected by using Analytic Hierarchy Process (AHP) method. The results of the research might facilitate the understanding of the support measures of smart specialization and the opportunities for sustainable development in rural areas, taking into account the level of the regional socio-economic development and the rate of development, as well as regional differences on the level of districts. The example of Latgale has shown that a small number of people and a low rate of development in most of the region districts simultaneously create both the acute need for and a great challenge in the sphere of sustainable development. By contrast, as a result of both the quantitative and the qualitative assessment the population has been recognised to be the main driving force of the development of rural areas in Latgale region.