AbstractTissue conductivity and permittivity are critical to understanding radio frequency (RF) power deposition during magnetic resonance imaging (MRI). These electrical properties are also important in treatment planning of RF thermotherapy methods (e.g., RF hyperthermia). The electrical properties may also have diagnostic value as malignant tissues have been reported to have higher conductivity and higher relative permittivity than surrounding healthy tissue. In this study, we consider imaging conductivity and permittivity using MRI transmit field maps (B1+ maps) at 3.0 T. We formulate efficient methods to calculate conductivity and relative permittivity from two‐dimensional B1+ data and validate the methods with simulated B1+ maps, generated at 128 MHz. Next, we use the recently introduced Bloch‐Siegert shift B1+ mapping method to acquire B1+ maps at 3.0 T and demonstrate conductivity and relative permittivity images that successfully identify contrast in electrical properties. © 2012 Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 41B: 13–21, 2012