Since 1980, numerous articles have discussed impact analysis; in addition, the Ontario Hospital Association and the Ontario Medical Association are about to publish guidelines to assess the impact of additional physician manpower and instructions on various techniques to conduct such an analysis. However, little has been published on medical manpower planning at the hospital level, in spite of the fact that a medical manpower plan is at the core of a successful hospital strategic plan. This article presents a population-service-based model of a medical manpower plan and reviews its use at Peel Memorial Hospital.