Oil and gas exploration and production activities in Vietnam have been boosted with many petroleum discoveries of large potential being put into development and production, contributing importantly to the country's socioeconomic development with a total production of 455 million tons of oil equivalent. However, there are still a number of small and marginal fields which are difficult for development in terms of economic, technical and legislative conditions. To ensure domestic oil and gas production output, it is necessary to encourage the participation of petroleum investors in the development and exploitation of these fields through an incentive mechanism, which would significantly contribute to the government revenue, improve the economic efficiency of projects and ensure energy security. This article presents a general concept of marginal fields, introduces international experience on marginal field incentives, and proposes policies to encourage marginal field development and production in Vietnam.