Health workforce planning is necessary in order to ensure that trained and knowledgeable health workers are available to deliver healthcare services when and where they are needed. Ensuring adequate human resources for health (HRH) is crucial in order to continue progressing toward the realization of the Millennium Development Goals. The purpose of workforce planning is to determine the most appropriate balance among the mix, distribution and number of health workers. As Thomas Hall has noted, workforce surpluses or shortages can decrease productivity and efficiency, deplete scarce resources and squander worker capabilities. Training health workers requires a significant investment of time and resources; therefore, restoring balance to a system in which the health workforce supply is out of sync with the demand for health services can be a lengthy process. In this context, health workforce projections can be very useful. The aim of this technical brief is to provide a rapid review of different health workforce projection approaches. A list of references serves as a guide for those who would like more information on this subject.