The number of students applying to medical schools is shrinking after rising steadily during the 1990s. The decline is the latest turn in the behavior of the applicant pool, which historically has gone through many cycles. Although government policies have strongly influenced the past behavior of the applicant pool, the more recent cycles appear to be related to changes in the Medical College Admission Test (MCAT) and labor market conditions. This article first reviews the cyclical nature of the pool and outlines some of the important factors that have influenced its patterns. Then it focuses on more recent data covering 1990-2000, showing how changes made in 1991 to the MCAT have affected the applicant pool. Data are presented to document the close relationship between the number of students taking the MCAT and the number of medical school applicants in subsequent years. Using this relationship, a projection model has been developed for making projections of the number of applicants for the entering class in osteopathic medical schools in future years. Actual data are compared to the model's projections.