The direct values of aquatic resources (freshwater) used in livelihood activities by rural households in Siem Reap, Cambodia were estimated using the net economic value method. The constraints faced by households to access these resources were also analyzed. Data used were from cross-section household survey, longitudinal monitoring, and participatory rural appraisal activities done among selected households from 2003 to 2004. In general, the study found that aquaticresources had substantial value in terms of income, employment, and overall livelihoods to households in both extractive and non-extractive activities. Among others, the study found that (1) fish catch per household was higher in the dry season than in the wet season and among higher wealth households than medium and lower wealth households; (2) livelihood activities earned positive net incomes even when labor was included as part of costs; (3) generally, labor formed a significant part of the costs of livelihood activities; and (4) the presence of fishing lots was the main access issue facing households in the use of aquatic resources. The study explored the implications of the results to the management and sustainable development of aquatic resources in Siem.