Lessons from integrated natural resource management (INRM) practiced at different scales are reviewed, with a focus on catchment management. INRM is complex, and many interactions have to be addressed. Consequently, the scale of investigation can restrict the generality and utility of the findings. Examples show that temporal, biophysical, and institutional scales can each be critical. Contexts and dynamics associated with particular scales, and interactions or lateral flows that become important with increasing scale, also pose serious challenges. A conceptual framework is presented for scaling issues in INRM and how to deal with them. To benefit many people over large areas within sensible time frames requires considerable political will, investment, and strategic planning from the outset. Only then will an enabling environment be created to meet a range of preconditions identified in previous studies of integrated catchment management, watershed development, common property management, and devolution. This paper focuses on the links between the organizational/human aspects and the biophysical/technical perspective of various scaling issues. In particular, there is a need to reconcile current top-down and bottom-up approaches, both of which are needed to achieve effective delivery in structured programs beyond the scale of a few villages or isolated success stories. Options for bridging this gap are discussed and recommendations are made for research that might be undertaken. Action research is recommended to enable learning-by-doing, and should focus at two levels: strategic studies to help create the political and institutional landscapes required for scaling-up; and specific studies of gaps in knowledge, in particular, programs that account for scale issues. These suggestions are illustrated using the example of groundwater management via nested scales of interdisciplinary research.