The issue of compatibility between buildings and environment is becoming primarily important. New buildings must comply with indications and rules concerning specific environmental requirements that are focused on the improvement of the quality of the building context and the quality of the areas used by occupants. ITC-CNR, the Construction Technologies Institute of the National Research Council, is actively dealing, both at national and international level, with the buildings sustainability issue. At national level the institute in involved in projects focused on the development of buildings sustainability certification systems based on Protocollo ITACA and SBTool Italia. At international level, ITC-CNR is involved in the working groups of SBAlliance, an international organization providing mutual recognition of the systems for the certification of the environmental sustainability of buildings. This paper presents the activities conducted by ITC-CNR at national level, in particular those related to the application of Protocollo ITACA. Protocollo ITACA is the evaluation system of the buildings sustainability adopted by the Conference of Italian Regions for the certification of the environmental sustainability of residential buildings. This system can be applied to several regional contexts and to different intended uses keeping the main structure of the protocol unchanged and with no alteration of the evaluation methodology based on the SBMethod. Protocollo ITACA can be applied starting from the initial design phases up to the end of construction of the building and it is based on the use of quantitative environmental sustainability indicators that are recognized at regulatory and legislative level. The methodological approach used in Protocollo ITACA encourages designers to optimize the building construction process in order to improve the quality of the building through architectural and technological strategies that reduce the impact on the environment.