One of the most widely used materials in construction worldwide is concrete. Due to its cheap manufacturing and high strength it has been extensively used, leading to environmental problems. Thus, various alternatives have been suggested to concrete made from Ordinary Portland Cement (OPC), one among them being Geopolymer Concrete. Geopolymers are inorganic alumino-silicate polymers synthesised from materials of geological origin or by-product materials such as fly ash which are rich in silicon and aluminium. Fly ash is available abundantly worldwide from thermal power plants whereas Ground Granulated Blast furnace Slag(GGBS) is obtained by quenching iron slag from a blast furnace in water or steam. Ferrochrome slag or charge chrome is a major solid waste generated from submerged electric arc furnaces during manufacturing of ferrochrome alloy. A major drawback of using fly ash based GPC is its requirement of high temperature for curing. The main purpose of this study was to evaluate the mechanical properties of ambiently cured fly ash based geopolymer concrete with ferrochrome slag partially replacing coarse natural aggregate and GGBS partially replacing fly ash. Present study indicates that the compressive strength increased with the increase in proportion of GGBS with respect to fly ash from 25 MPa at 10% replacement to 50MPa at 40% replacement.