Since 1977, the Smithsonian Institution has had a major research program on the human biological history of the Near East. As part of this program, electromagnetic (EM) surveying methods have been extensively used to identify anomalies of potential archaeological significance below the surface. An EM-31 non-contacting terrain conductivity meter was used in Jordan, Bahrain, Kuwait, and Egypt with excellent results.In addition to the successful application of EM equipment to archaeological problems, we investigated the equipment's response to changing environmental and climatic conditions. We have developed efficient methods for recording EM data. The following results were obtained. Recording accuracy is better than previously reported (0.97 percent repeatability error between two observers); the degree of accuracy is primarily a function of operator error and less a function of equipment reliability; and the EM-31 produces helpful, highly reproducible results in the arid and semiarid environment of the Middle East.