The number of data centres is rapidly increasing, driven by economic growth, the surge in data demand—particularly from edge computing (where data is processed closer to users via smart devices)—and the rise of as artificial intelligence. Since 2019, the number of internet users worldwide has more than doubled, while global internet traffic has expanded to 5.5 billion people worldwide. This rising energy demand contributes significantly to greenhouse gas emissions and environmental impacts. Against this background, UNEP’s United for Efficiency (U4E) initiative has developed the Sustainable Procurement Guidelines for Data Centres and Servers. These Guidelines provide a starting point for government institutions and procurement authorities consider. They focus on key performance criteria and operating conditions that are most relevant and impactful for the selection of energy-efficient data centres and computer servers.