In recognition of the need to develop approaches to environmental impact assessment that are both proactive and which take a wider view of environmental change and its causes, there has been increasing interest in the concept of cumulative environmental change and its assessment. We outline a definition and conceptual framework for the analysis of cumulative environmental change. The contribution of geographical information systems (GIS) to the assessment of cumulative effects is considered. The potential is then illustrated by reference to an example of the use of GIS in respect of cumulative effects assessment for a small area of New Zealand. The attendant problems of using GIS in this context are identified and discussed.