The performance of computing equipment continues to increase following Moore’s law of doubling the performance every 18 months. The performance improvements achieved by the semiconductor and computer manufacturers stand alone among any other industry for achieving increased performance over a sustained period of time. However, these increases in performance have a downside in that it has caused a significant increase in heat dissipated by the computing equipment, such that it is becoming very difficult to cool these systems in data centers or telecommunications rooms. Some of the highest powered systems are dissipating upward of 2500 W/ft²(27,000 W/m²) based on the equipment footprint. When systems dissipate this amount of heat and then are clustered together within a data center, significant cooling challenges can result. This paper describes the thermal profile of a 76 ft × 98 ft (23.2 m × 29.9 m) data center and the measurement techniques employed to fully capture the detailed thermal environment. In a portion of the data center(16 ft × 26 ft 4.9 m ×7.9 m), which encompasses very high powered servers, the heat flux is 512 W/ft²(5500 W/m2). Most racks within this area dissipated approximately 19 kW. Detailed measurements were taken in this data center of electronic equipment power usage, perforated floor tile airflow, cable cutout airflow, computer room air-conditioning (CRAC) airflow, and electronic equipment inlet air temperatures. In addition to these measurements, the physical features of the data center were recorded such that a detailed CFD model could be employed to compare the results (this will be the subject of a follow-up paper).