BackgroundOverweight and obesity in preschool children have increased worldwide in the past two to three decades. Child Health Centers provide a key setting for monitoring growth in preschool children and preventing childhood obesity.MethodsWe conducted semi-structured interviews with 15 nurses working at Child Health Centers in southwest Sweden in 2011 and 2012. All interviews were tape recorded and transcribed verbatim and imported to QSR N’Vivo 9 software. Data were analyzed deductively according to predefined themes using content analysis.ResultsFindings resulted in 332 codes, 16 subthemes and six main themes. The subthemes identified and described barriers and facilitators for the prevention of childhood obesity at Child Health Centers. Main themes included assessment of child’s weight status, the initiative, a sensitive topic, parental responses, actions and lifestyle patterns. Although a body mass index (BMI) chart facilitated greater recognition of a child’s deviant weight status than the traditional weight-for-height chart, nurses used it inconsistently. Obesity was a sensitive topic. For the most part, nurses initiated discussions of a child’s overweight or obesity.ConclusionCHCs in Sweden provide a favorable opportunity to prevent childhood obesity because of a systematic organization, which by default conducts growth measurements at all health visits. The BMI chart yields greater recognition of overweight and obesity in children and facilitates prevention of obesity. In addition, visualization and explanation of the BMI chart helps nurses as they communicate with parents about a child’s weight status. On the other hand, inconsistent use and lack of quality assurance regarding the recommended BMI chart was a barrier to prevention, possibly delaying identification of overweight or obesity. Other barriers included emotional difficulties in raising the issue of obesity because it was perceived as a sensitive topic. Some parents deliberately wanted overweight children, which was another specific barrier. Concerned parents who took the initiative or responded positively to the information about obesity facilitated prevention activities.