Good workforce planning is a characteristic of modern and dynamic human resource management. This chapter analyses the main strengths and windows of opportunity of workforce planning in the Brazilian federal government, in the light of the experience of OECD countries. The discussion includes: the size and costs of the workforce in the federal government; the accounting methodology of public employees and their costs; the challenges for proper strategic workforce planning; the promotion of a whole-ofgovernment approach for increasing efficiency and reducing the costs of the public workforce; the pay-setting process as part of the cost management strategy; the role of the unions in setting employment conditions; the need to adjust the public service to an ageing society and workforce; the modernisation of the public service pension system; and the promotion of diversity as a strategy to ensure the right competences and skills in the public service.