Joint management of protected areas by indigenous people and government management agencies is being promoted at the international level as a tool to strengthen the protection of biodiversity and the recognition of indigenous peoples' interests in protected areas. Monitoring and evaluating the effectiveness of joint management is, however, in its infancy. To help managers, we calculated the costs of participatory monitoring and evaluation (PM&E) of joint management in the Northern Territory (NT), Australia relative to other joint management expenses. Costs of the process constituted only 1.3-1.5 per cent of the total joint management budget of over AU$10 million over three years. The preparation and validation/feedback phases of PM&E demanded most time and money, with contractor costs, particularly for external facilitators, representing the largest proportion of expenditure. The relatively low costs of PM&E are in contrast with common perceptions of the process as time-consuming and expensive.