From January 27 to 29, 1997, experts on allergen immunotherapy from various geographic locations throughout the world met at the headquarter of the World Health Organization (WHO) in Geneva, Switzerland to reach a consensus on international guidelines. Guidelines or indications for immunotherapy with inhalant allergens and venoms have been published before by the WHO, the European Academy of Allergy and Clinical Immunology (EAACI), the International Consensus Report on Asthma, the Global Strategy for Asthma Management and Prevention, the International Consensus Report on Rhinitis, the British Society for Allergy and Clinical Immunology, the American Academy of Allergy, Asthma and Immunology (AAAAI) and the American College of Allergy, Asthma and Immunology (ACAAI). The committee wrote a position paper based on scientific articles reviewed for data before April 1, 1997. These guidelines should result in a better understanding of the science and rationale for using allergen immunotherapy as well as improve the safety of such therapy. The document also defines new techniques being developed which may result in better efficacy and less risk for allergen immunotherapy as well as recommends areas of additional and necessary research.