This article examines experiences and dilemmas encountered by school nurses when applying motivational interviewing in counseling sessions with overweight children and their parents. Motivational interviewing is a counseling method used to bring behavior change by school nurses for preventing obesity in children. . The study design is a qualitative case study based on a purposive sample of interviews with school nurses. The semi-structured interview format gain a deeper insight in school nurses practices and experiences with applying motivational interviewing in their daily work. Three dilemmas for school nurses were revealed: when the child was severely overweight and the parents did not perceive this as a problem, when the child and the parents were at different stages of motivation to change, and when applying an individualized approach such as motivational interviewing for preventing a complex societal problem, in this instance obesity. The study raises an important issue to consider, with implications for school nursing and obesity prevention: motivational interviewing as either a counseling method or a prevention strategy. One dilemma for the school nurse is when a child is identified as overweight by screening, and it is not perceived as a problem by the parents nor the child. On one hand, the nurse does not want to impose a situation on either the child or parents that they themselves do not regard as a problem and potentially stigmatize the child by talking about it. Our study raises two issues in considering the implications for school nursing with respect to using motivational interviewing as a means of preventing obesity in the school age population as either a counseling method or a prevention strategy. Motivational interviewing as a counseling method for preventing childhood obesity was adapted by school nurses and integrated into their practice along with other methods they knew from the past. However, it was also associated with ethical dilemmas when parents did not perceive the identified state of being overweight as a problem, and when child and parents were at different stages regarding motivation to behavioral change. Thus, the potential for motivational interviewing as an obesity prevention strategy in school nursing must remain under active consideration.