To remove cascading effect of taxes and provide a common nation-wide market for goods and services, India is moving towards introduction of Goods and Services Tax (GST). Under the proposed indirect tax reform both Central and State Governments will have concurrent taxation power to levy tax on supply of goods and services. It is expected that the proposed regime will improve tax collection and minimize leakage, as both Central and State Tax Administrations will monitor and assess the same set of taxpayers. There are several challenges before introduction of GST and these can be classified into two broad heads – a) GST Design and Structure related, and b) GST Administration and Institutional. On design related issues, broad consensus on choice of revenue neutral rates (RNRs), harmonization of GST rate(s) across States, harmonization of list of exempted and excluded goods and services and thresholds for mandatory GST registration across States are yet to be reached. Similarly, there are several issues involved in tax administration (between Central and State Tax Administrations and also across State Tax Administrations) which are not yet solved. Taking cognizance of discussion available in the public domain this paper attempts to provide a broad contour of the proposed GST regime and highlights major challenges which require immediate attention of the Governments.