Energy consumption in the buildings sector is very high and is expected to increase further due to improvements in living standard and increase in the world's population. Incorporating appropriate solar passive features in climate responsive buildings are good options for energy conservation. This kind of building design integrates the micro-climate and architecture with human thermal comfort conditions and improves the building energy efficiency. From ancient times, people have used solar passive techniques in vernacular architectures throughout the world. However, still there is a lack of understanding, both in qualitative and quantitative aspects of solar passive techniques in vernacular architectures of North-Eastern India. A field study has been carried out to find out the various solar passive features in these naturally ventilated vernacular buildings in different bioclimatic zones of the region. The methodology of this work consists of survey of 150 households (50 houses in each bioclimatic zone) and, interacting with 300 occupants in each zone. The photographic evidences of solar passive features in these buildings are also collected. In this paper, the solar passive features related to building form and orientation, envelope design, shading, use of natural ventilation, internal space arrangements and activities of the habitants are explained for all the climatic zone of the region. (C) 2011 Elsevier Ltd. All rights reserved.