In this paper a Terahertz T ime-Domain measurement system has been used to perform Tomographic imaging of pharmaceutical compounds with coating. Measurements on paracetamol and ibuprofene samples are done both in transmission and reflection geometries and their capabilities are compared. Results of the contrast reconstructions provide information of the relative permittivity of the pharmaceutical compounds. T he interfaces between materials with different permittivities are detected, thus allowing characterization of different layers of the compound.