Professional requirements for physicians specializing in allergy were estimated to assist policymakers in developing guidelines for graduate medical education. In estimating service requirements for allergy, an allergy Delphi panel reviewed reference and incidence-prevalence and utilization data for 21 conditions that affect the ambulatory care practice of the allergist. After adjusting incidence-prevalence rates, panelists reviewed data on the percentage of persons with each condition requiring health care, and, in particular, the medical services of the allergist. Leading ambulatory problems were identified, and delegated visits by condition were estimated. The final estimates of the allergy Delphi panel implied 2,327 allergists required in 1990, not accounting for the impact of the pediatric allergist. Based on a generic adjusted-needs based model, a final estimate of allergists required for 1990 was between 1,900 and 2,200. Appendices include: lists of members of the Graduate Medical Education National Advisory Committee and members of other technical panels, information on the procedure for calculating internal medicine subspecialty ambulatory requirements, ambulatory care data from the Delphi panel, reference notes, and a bibliography. (SW)