This paper will discuss the impact of considering carbon emissions on the design of sustainable supply chain network. Traditionally, supply chain network design attempts to determine the location and the capacity of the suppliers, plants, and DCs as well as the allocation of the customers to DCs so as to maximize the long term economic performance of the company. In this paper, we present a supply chain network optimization model to support decisions that take into account both cost and carbon footprint. We analyze a variety of settings where the carbon footprint has major impact on the design and configuration of the supply chain. These models can be used by individual firms to reduce their individual carbon footprints (or to adhere to restrictions on carbon emissions) without compromising profitability.