To what extent do rural people in developing countries depend on forest environmental income? This study addresses this question through a meta-analysis of 51 case studies from 17 countries. Cases were selected on the basis of a broad literature search, focusing on (i) data on household environmental income as well as other income sources;, (ii) productive assets and socio-cultural information; and (iii) information on contextual variables that are likely to influence the use of forest sources of income. Results reveal that forest environmental income represents on average 22% of the total income in the population sampled. The main sources of forest environmental income are fuelwood, wild foods and fodder. Forest environmental income has a strong equalizing effect on local income distribution. Income diversification declined with total income; diversification did, however, increase with dependence on forest resources up to a point, beyond which diversification declined. The partial or complete omission of environmental income in current poverty assessments may lead to an underestimation of rural income and, under certain circumstances, to flawed policies and interventions. (C) 2006 Elsevier B.V. All rights reserved.