Carbon nanomaterials possess great potential to be used in variety of fields. Our group focuses on using various carbon nanomaterials to enhance imaging properties of a variety of MRI and CT-based contrast agents. The present study demonstrates that carbon nanomaterials, including single-walled carbon nanotubes, double-walled carbon nanotubes, multi-walled carbon nanotubes and graphite, associate with the imaging active agents and enhance their ability for medical imaging. For CT imaging agents we have focused on iodine and for MRI agents gadolinium, manganese, erbium and chromium. In addition to the synthesis, physical characterization, and imaging properties, the results from the in-vitro analysis of the different materials will be presented.