This manual is a revision of an earlier Workload Indicators of Staffing Need (WISN) user’s manual, which was prepared by Peter Shipp and published by WHO in 1998. The WISN method is based on a health worker’s workload, with activity (time) standards applied for each workload component. This revised manual was published in 2008, and takes into account the now-decentralized nature of health management in many countries. It is thus intended for the wider range of managers working in today’s health systems. Its preparation has benefited greatly from the development of an Indonesian WISN toolkit, which was used at the local level in that country. The WISN method takes into account differences in services provided and in complexity of care in different facilities.