While temporary work has experienced a spectacular rise in France in the last forty years, the emergence of temporary employment agencies in the social and medical-social sectors has appeared much later and has so far remained relatively marginal. However, the appearance of these service providers, essentially subcontractors of social services, is unexpected in a sector based on organizational principles and relations to their public(s) that are far removed from the characteristics of intermittent work. Based on a four-year ethnographic research, this article revisits the significant aspects of temporary work in children’s social services by a joint analysis of specific positions of temporary employment agencies in this sector and their impacts on relational activity.