Bangladesh is predominantly a rural based country. In Bangladesh like any other part of the world, traditional architecture shows its sustainability with their harmonic balance within the surrounding society and climatic environment and also with their specific characters of forms and spatial relationships. Generally the traditional rural houses are designed and formed based on the way of life of rural people, their social ethos and response to the local resources, and to the climatic elements. The climate of the Bangladesh is tropical “warm-humid”. During the summer months the temperatures are high and the sun is directly overhead. The winter months are moderately cold. The major passive system strategies of traditional rural houses in Bangladesh are the use of locally available materials having good insulation and cooling properties, cross ventilation, open court yard and surrounding vegetations which are very effective in providing thermally comfortable environment inside and outside spaces of the houses. The principle and techniques of those passive systems of traditional houses can be employed in the modern houses of the country as a step towards energy efficiency and better indoor air quality. This paper presents the passive systems of the traditional rural houses in Bangladesh with particular focus on the construction materials used based on the regional climatic condition, natural ventilation and other passive cooling techniques.