This dissertation assesses the contribution of fish and forest products in the livelihoods of villagers in Strung Treng province of Cambodia, as these two common pool resources are threatened by the construction of the Lower Sesan 2 hydropower project. Household survey data collected under the Challenge Program on Water and Food (CPWF) are used in the analysis. It is found that, in general, fish accounts for a higher overall contribution in household’s livelihoods compared to forest products. Fishery products are most important for direct consumption, while forest products are more important for cash income. Across the study area, the households that most heavily extract and depend most on these resources are the relatively poorer households. The households that highly depend on forest products are distinct, however, from the households that highly depend on fish. The results indicate that these households’ livelihoods are vulnerable to changes in the quality of common pool resources or restriction in access to them due to implementation of the Lower Sesan 2 hydropower project. Compensation and income generation programs that can ensure food security and substitute for losses of common pool resource-based income are a necessity for impacted households. In addition, further restrictions on accessing common pool resources should be minimized in order to secure rural livelihoods and reduce poverty.