The aim of the thesis is to explore how lean principles can be applied in the work of RPO services in order to address the problems that are present in the labor market. Value stream mapping was used to distinguish between useful work and non-value-adding activities, focusing on what the client pays for. To identify possible sources of inefficiency, the theory of 7 types of waste in lean was applied to RPO services. The 5S method was used to suggest performance enhancing actions and to support the path toward continuous improvement. Finally, possible KPIs were listed to best promote and measure the business efficiency and operations of RPO providers.