OBJECTIVE: In Uganda, formal and informal private practitioners (PPs) provide most case management for childhood illness. This paper describes the impact of negotiation sessions, an intervention to improve the quality of PPs' case management of childhood diarrhoea, acute respiratory infection and malaria in a rural district in Uganda. METHOD: Negotiation sessions targeted PPs working at private clinics and drug shops. The aim was to improve key practices extracted from the national Integrated Management of Childhood Illness Guidelines, and to measure the PPs' performance before and after the intervention. RESULTS: Post-intervention the quality of case management for childhood diarrhoea, acute respiratory infection and malaria was generally better, although certain practices appeared resistant to change. We discovered various types of PPs who were mostly unregistered by the district authorities. CONCLUSIONS: Results suggest the importance of maintaining ongoing monitoring and support to PPs to understand barriers to change and to encourage more practice improvement. Modifications to the intervention are needed to take it to scale and render it more sustainable. Getting local organizations and professional associations more involved could make it easier to establish and maintain contact with PPs. The government needs to simplify registration procedures and reduce associated fees to encourage PPs to register and thus be included in a large-scale intervention. Future interventions need to measure the impact on improving childhood case management at the community/household level.