Building productive capacities is a top priority for least developed countries to promote development and graduate from the status of least developed country. This paper discusses the challenges and the opportunities for these countries to build their productive capacities. It argues that the main challenge is to manage the long-term effects of the increase in the terms of trade of commodities and reduction of terms of trade of manufactures, which threaten their growth trajectory. The paper presents a method to identify the opportunities for diversification that promotes the generation and acquisition of productive capacities. It also presents a list of potential new products and export markets that could be targeted by government and private sector for achieving higher long-term gains.