School nurses meet obese children in their everyday work. Although school nurses acknowledge the importance of getting hold of school children's obesity, they seem to lack strategies enabling them to handle the delicacy of the problem. The aim of this study was to describe how school nurses perceive their work with obese children with support of an action plan. Qualitative in-depth interviews were performed with six school nurses working in a municipality, where an action plan for the work with obese school-age children had been implemented. The transcribed data was analysed by a manifest content analysis. The results showed that the informants perceived having a key role in the obesity work, which they experienced as meaningful, but full of pitfalls. They found themselves suitable for the task, but perceived lacking deeper knowledge about specific modes of work such as motivational conversation. As the task was considered delicate, there were great demands for guidelines, education and cooperation. The action plan served as support for maintaining professional confidence throughout the process, but there was room for improvements.