A joint inverse module was developed by imposing structural similarities between different physical parameters and incorporated into the E4D geophysical simulator, a parallel multi-physics modeling and inversion code with unstructured tetrahedral mesh. The inversion capability of E4D can accommodate joint inversions of data from two or more geophysical methods that are available in E4D and is suitable for large scale three-dimensional subsurface characterization or monitoring. The joint inversion capability were tested using synthetic data from borehole electrical resistivity tomography and seismic survey.