Almost all development organisations are expected to have systems that enable them to collect, analyse, summarise and use information. However, whilst there is a large and growing range of resources covering monitoring and evaluation (M&E), there is little guidance or support for those wishing to design M&E systems. The guidance that is available tends to focus on systems at project or programme level, rather than at country, regional or international levels. This paper attempts to redress this imbalance by describing a methodology that can be used to design an M&E system within a complex organisation.