Audiomagnetotelluric (AMT) soundings at Quest caldera were made in the course of a mineral resource study of the Columbine-Hondo and Latir Peak Wilderness areas, New Mexico, in the fall of 1980 and 1981. This regional electrical survey covered an area of approximately 518 km2 and a consisted of 92 AMT stations at an average spacing of approximately 3 km. An AMT apparent resistivity map and one-dimensional models delineate several major lithologic and structural features. A large north-south resistivity high is interpreted to outline a largely concealed batholith 20 km long, 2--6 km wide, and >4 km thick. Two high-resistivity east-west trends coincide with the mapped margins of the Questa caldera, indicating the electrically contrastig rocks at its boundary. Apparent resistivity lows coincide with areas of hydrothermal alteration known to contain stockwork molybdneum deposits.