In a Nordic context few historical studies have reported on teachers views on children’s problems. This presentation draws on a document-analysis of teachers reports on children having behavioral problems in the Municipality of Copenhagen in the 1950s and 1960s. The children were referred to three Observation Colonies situated outside the city. Whereas historical research previously has focused either on regimes of testing (Axelsson, 2007; Ydesen 2011; Ydesen et al. 2013; Canales & Polenghi 2019) or on how professionals like psychologists and psychiatrists have labelled children (Hamre & Ydesen 2014; Hamre 2019; Bakker 2020). Applying Michel Foucault theoretical framework and methodology of problematization (Foucault 1997;1998) the study examines how teachers at special schools historically have contributed to the problematization of children’s behavior, and this leads to interventions. The expected outcome for the study is a contribution to an analysis of the emergence of interprofessional collaboration as a technology in the Nordic welfare state’s shaping of future citizens.