Background. A cluster randomised trial was conducted to determine the effectiveness of locally adapted practice guidelines and education about paediatric asthma management, delivered to general practitioners (GPs) in small group interactive workshops. Methods. Twenty-nine practices were randomly allocated to one of three study arms. Australian asthma management guidelines were adapted to accommodate characteristics of the local area. GPs in the intervention arm (Group 1, n = 18 GPs) participated in a small group based education program and were provided with the adapted guidelines. One control arm (Group 2, n = 18 GPs) received only the adapted guidelines, while the other control arm (Group 3, n = 15 GPs) received an unrelated education intervention. GPs' knowledge, attitudes and management of paediatric asthma was assessed. Results. Post intervention, intervention arm GPs were no more likely to provide a written asthma action plan, but were better able to assess the severity of asthma attack (Group 1vs Group 2 p = 0.05 and Group 1 vs Group 3 p = 0.01), better able to identify patients at high risk of severe attack (Group 1vs Group 3 p = 0.06), and tended to score higher on the asthma knowledge questionnaire (Group 1 vs Group 2 p = 0.06 and Group 1 vs Group 3 p = 0.2). Most intervention arm GPs felt more confident than control GPs to manage acute asthma attack and ongoing management of infrequent episodic asthma. Conclusion. Using interactive small group workshops to disseminate locally adapted guidelines was associated with improvement in GP's knowledge and confidence to manage asthma, but did not change GP's self-reported provision of written action plans.