Computational phantoms of the human body in association with radiation transport codes are widely used in dosimetry. In the late 1980s, voxel phantoms derived mostly from medical image data of real persons were introduced. A voxel phantom contains a huge number of tiny cubes (few millimetres or less) grouped to represent various anatomical structures. As they provide more realistic and detailed information about the human anatomy than former stylized phantoms, ICRP has adopted voxel phantoms as computational representation of the adult reference person (ICRP, 2007). The ICRP Reference Male and Reference Female voxel phantoms were released in 2009 (ICRP, 2009). This presentation will give a short overview of the development of voxel phantoms and their use in dosimetry. Advantages and limitations of voxel phantoms will also be exposed. Finally, ongoing activities on numerical phantoms within EURADOS WG6 (computational dosimetry), with a special focus on the intercomparison exercise on the usage of the ICRP/ICRU adult reference computational phantoms, will be presented.