OBJECTIVE: Concern has been raised about the potential impact of nanomaterials exposure on human health, and France has decided to implement a timely epidemiological surveillance tool of workers likely to be exposed to engineered nanomaterials that could accompany the development of nanotechnologies. METHODS: A comprehensive review of the toxicological and epidemiological literature has been conducted together with an exploratory study among French companies producing or handling nanoobjects. RESULTS: A double surveillance system is proposed consisting of a prospective cohort survey and repeated cross-sectional studies. The aim of the cohort is (1) to monitor long-term health effects and (2) to allow of further research. Setting-up an exposure registry is the first planned step. CONCLUSIONS: The protocol is about to be submitted to the French Government for approval and funding. (R.A.)