This paper reflects on the debates and the practices involved in monitoring and evaluating energy for development projects which led to the formulation of "A Guide to Monitoring and Evaluation for Energy Projects" by an international working group. Another purpose of the paper is to invite energy policy-makers. planners and implementers to engage with the meaning of good practice in monitoring and evaluation in the energy sector and the capacity building necessary to achieve this. This paper begins with definitions of monitoring and evaluation and discusses the reasons for conducting such studies and the benefits to be gained. This paper then highlights selected approaches to monitoring and evaluation and the conditions under which each might be useful, and how and by whom lessons are to be learned. Attention is paid to key elements of monitoring and evaluation such as the development of indicators and the measurement of impacts. In the light of the many failed energy projects, this paper closes with some suggestions of how monitoring and evaluation processes and capacity may be improved. (C) 2008 Published by Elsevier Ltd.