In countries such as India, local health systems struggle to utilise their resources optimally and to deliver quality health services in an effective manner. While the reasons for these are many, poor health management capacity has been postulated to contribute to this problem. Understanding how public health organisations can move towards change through capacity building interventions is crucial to strengthening health systems. By studying a capacity building intervention of health managers in Tumkur district of southern India using realist evaluation approach, we advance the understanding of how these interventions could contribute to organisational change. We find that capacity building programmes need to go much beyond transfer of knowledge and skills in order to effect organisational change and identify several individual and institutional factors and various alignments within decentralising local health systems that are crucial to achieving change. We conclude that human resources management strategies in Karnataka ought to invest in altering workplace conditions and organisational culture through restructuring the current health bureaucracy so that committed health managers could better utilise change opportunities presented by capacity building programmes. (SP - Sciences de la santé publique) -- UCL, 2015