A series of scientific meetings dealing with the effects of chemicals on the immune system were organised by the IPCS with several international and national partner institutions over the years. The overall aim was to consider ways of integrating new scientific evidence on this rapidly developing area of work, as it emerges, into risk assessment practices. The first international seminar on the immune system as a target for toxic damage was held in Luxembourg in 1984 (UNEP, ILO, WHO:IPCS, CEC, 1987). This was followed by an International Workshop on Immunotoxicity of Metals and Immunotoxicology, held in Hannover, Germany, in 1989 (IPCS, 1990). In 1992 a Workshop on Allergic Hypersensitivity Induced by Chemicals was organised in Bilthoven, Netherlands, jointly supported by IPCS and the WHO European Centre for Environment and Health (Vos et al., 1995). Two special joint workshops of IPCS and the Norwegian National Institute of Public Health were held in Oslo in 1995 and 1996, the first on ‘Environmental Chemicals and Respiratory Hypersensitisation’ (Dybing et al., 1996), and the second on ‘Chemical Exposure and Food Allergy:Intolerance’ (Lovik et al., 1997). Finally, a scientific symposium on epidemiology and immunotoxicity, jointly organised with the National Institute of Public Health and Environmental Protection of the Netherlands, was held in Bilthoven in 1997 (Van Loveren et al., 1999). In parallel, two Environmental Health Criteria monographs on ‘Principles and Methods of Assessing Direct Immunotoxicity Associated with Exposure to Chemicals’ (IPCS, 1996), and ‘Principles and Methods for Assessing Allergic Hypersensitisation Associated with Exposure’ appeared (IPCS, 1999).