This guidance note is intended to assist practitioners with effective use of cost indicators in donor programmes with an infrastructure component; with a focus on the challenges experienced in Fragile and Conflict Affected States (FCAS). It explains how to use cost indicators at each stage of the infrastructure investment lifecycle; as a tool to better understand and improve a programme’s value for money (VFM). Recommendations are based on good practice economic principles, and are also of use in non-FCAS contexts.