Objective: Insufficient asthma management leads to impaired health-related quality of life (HRQL). The aim of this study is to assess whether individualized self-management (ISM) support will improve HRQL in children with asthma compared to enhanced usual care (EUC) in Dutch general practices. Methods: A cluster-randomized controlled trial with 9-month follow-up. ISM is a nurse-led intervention that is optimized to the needs of children, leading to a written action plan. Power calculation demanded inclusion of 170 children (aged 6-11 years) diagnosed with asthma and active medication use. Results: Outcomes were HRQL of the child (Paediatric Asthma Quality of Life Questionnaire, PAQLQ-s) and several secondary outcomes. Data of 29 children (mean age 8.6 years, SD 1.7) were analyzed; ISM (n = 15) or EUC (n = 14). Logistic regression analysis (minimal clinical important difference; MCID > 0.5) and descriptive analyses were performed. Despite high PAQLQ-s score at baseline (median ISM 6.35, EUC 6.02), a substantial number of subjects from both groups showed MCID of HRQL (ISM 33%, EUC 57%). Treatment differences on HRQL were not significant (OR 0.38, 95% CI 0.08, 1.69). Secondary outcomes did not show significant differences either, with exception of PAQLQ-s symptoms domain score in favor of EUC. Conclusion: Due to recruitment problems and underpowered analyses, no firm conclusions on the effectiveness of ISM support for childhood asthma in primary care could be drawn. Still, this study can be considered a valuable pilot study and in the future, there might be better capacity in general practices to commit to such treatment.