Thirty new MT soundings were carried out in SW Iberia allowing the investigation of the lateral continuity of some major structures and lithological features that are believed to control decisively the deep architecture of the Ossa Morena Zone belts. Results of the two-dimensional inversion of the data reveal high-conductivity zones in the middle-lower crust, interpreted as the signal of a granulitic basement with grain-boundary interconnected films of graphite. The resistive features, located preferentially in the upper-middle crust, are ascribable to igneous complexes of variable age.