Environmental degradation can inflict serious damage on poor people, because their livelihoods often depend on natural resource use, and their living conditions may offer little protection from pollution of the air, water and soil. At the same time, povertyconstrained options may induce the poor to deplete resources and degrade the environment at rates that are incompatible with long-term sustainability. In such cases, degraded resources may precipitate a downward spiral, by further reducing the income and livelihoods of the poor. This "poverty-environment nexus" has become a major issue in the recent literature on sustainable development. In regions where the nexus is significant, jointly addressing problems of poverty and environmental degradation may be more cost-effective than addressing them separately. Empirical evidence on the prevalence and importance of the poverty-environment nexus is sparse, because the requisite data are often difficult to obtain in developing countries. In this paper, we use newly-available spatial and survey data to investigate the spatial dimension of the nexus in Cambodia, and Lao PDR. Our data enable us to quantify several environmental problems at the district/ provincial level. In a parallel exercise, we map the provincial distribution of poor households. Merging the geographic information on poverty and the environment, we search for the nexus using georeferenced indicator maps and statistical analysis. Our results suggest that the nexus is country-specific: Geographical, historical and institutional factors may all play important roles in determining the relative importance of poverty-environment links in different contexts. Joint implementation of poverty and environment strategies may be costeffective for some environmental problems, but independent implementation may be preferable in many cases as well. Since our search has not revealed a common nexus, we conclude on a cautionary note. Our evidence suggests that the nexus concept can provide a useful catalyst for country-specific work, but not a general formula for program design.