Diversity in primary energy sources in South Asian countries and their electricity demand patterns both  time-of-day as well as across different seasons open up opportunities for greater use of cheaper and cleaner  resources for electricity generation reducing fossil fuel use in the region. Such sharing of resources through  electricity trading requires electricity transmission system strengthening including planning and development  of cross-border transmission lines. The paper presents the economic and reliability benefits of electricity  trading among the South Asian countries with case studies involving six cross-border transmission lines.