The study is about how social workers perceive their power to be partly expressed and partly handled in the meeting with guardians in advance assessments in child welfare cases. The data collection was done through eight semi-structured interviews, which were done with a question guide. The question guide was designed so that we could answer our study´s questions. The analysis was done using a qualitative content analysis. As a theoretical framework we used Foucault's theory regarding power. The results of the study showed that the power expresses itself by sending summons to guardians. But also through the law and the guardian's fear of social workers' knowledge, as well as due to the guardian's ignorance regarding advance assessments. The results of the study also showed that social workers manage power by helping the guardian create trust in the social worker, motivating the guardian. Social workers also manage power by explaining the situation, listening, changing the focus and being clear through, for example, threats about their power to open a childcare investigation.