It is considered that the materials with new properties may lead to novel biological effects or unknown adverse health effects. To gather proper hazard information, it is important to develop both experimental protocols and detection/measurement methods for nanomaterials in the body, in parallel. Since 2005, we are running research projects to develop methods to monitor health risk effects for the assessment of manufactured nanomaterials funded by the Ministry of Health, Labour and Welfare. For the experimental protocols, these projects focus on the development of 1) in vitro experimental systems, 2) in vivo experimental systems (mainly focusing on long-term health implication, especially carcinogenesis), and 3) proper inhalation system. Firstly, fullerene (C60), titanium dioxide and multi-walled carbon nanotube were chosen to be tested because of their high production volume. Safety issues for new materials such as nanoparticles is a new paradigm. The key is that the full scale exposure to the public has not been started yet. Therefore, there is a good chance that information from hazard identification studies can be directly fed back to the product development plan. Manufacturers can produce safer products without risking themselves waiting for the toxicology studies to be finished after their products are widely marketed.