Buildings consume energy in their life cycle right from construction to demolition. Calculating the embodied energy provides a good indicator of the environmental impact of any structure. This paper compares the embodied energy from cradle to handover stage, of precast and cast-in-place floor slabs for an upcoming sports complex at a Indian Institute of Technology, Madras. The findings show that the energy expended for the precast floor slab is 10 % less than the cast in place floor slab, with manufacturing embodied energy of raw materials accounting for more than 90 % of the energy use. Although transportation of the slabs required greater energy in precast construction, it was more sustainable given the lower quantity of materials and the more efficient manufacturing and construction practices. As we work on ways to develop more sustainable buildings, precast construction may prove to be a very effective option.