The concept of calculating embodied energy because it's a wholistic method of measuring the sustain ability factor of building materials. By definition, the embodied energy is the sum of all the types of energy consumed while producing a specific product or a service. Mud concrete block is a novel walling material and there are few studies on embodied energy calculations for cement stabilized soil walling materials. In this study, the embedded energy of mud concrete block and other most industrious walling materials such as brick and cement block were calculated and compared concording to the source of their energy. The process analysis and hierarchical structure of energy consumptions were used to account the total embodied energy content. Ten feet (length) by ten feet (width) wall (hundred square feet) was used to compare the energy content. The brick is the highest embodied energy walling material. The mud concrete block has the lowest on account of transport of raw materials (cement) from the factory and the already embedded energy of cement. The cement has intermediate level of embodied energy. The extended research was carried out to find out the sustainability of the energy sources used to build these walling materials. The brick production was done using more or less sustainable energy sources such as biomass. Biomass is a renewable energy source and its fairly cheaper energy source in Sri Lanka. But mud concrete block and cement block using nonrenewable energy sources can be replaced by renewable energy sources and developed into more sustainable walling materials. (C) 2016 Elsevier B.V. All rights reserved.