The data acquisition system for the Hot Dry Rock Geothermal Energy Project at Fenton Hill, in northern New Mexico, has evolved to a computer controlled system complete with visual displays and emergency alarms. The system is comprised of two units. One unit monitors all surface facilities and during and energy extraction experiment is on-line 24 h a day. The other system is used for specialized downhole experiments. The data acquisition system is operator oriented so that a minimum crew can maintain the system