This paper describes the development and the institutionalisation of a participatory approach to innovation development and extension which took place through an action learning process in Zimbabwe. In order to scale up this approach through institutionalisation within the agricultural extension department it was necessary to adopt a complex and multi-faceted strategy. The development of 'learning cases', the exposure of extension officers to these cases, as well as deliberate trespassing and provoking action were means used to raise awareness and commitment for change. An informal network ofprojects which were all pursuing participatory development acted as a lobby group to strengthen the influence of the approach and bring it into mainstream thinking. Once commitment for change had developed in the extension department, operationalisation of participatory extension approaches became a major challenge. This reform required substantial changes in the organisational culture, roles, relationships and attitudes of individuals and groups. Changes of that nature are presently being addressed in an organisational development programme within the extension department, which includes a learning process to facilitate behavioural and attitudinal changes. The paper concludes that the institutionalisation and operationalisation of participatory approaches takes far more than simply the training of staff in participatory methods. These are complex interventions which require considerable commitment from all actors, sound strategies, flexible methodologies, a conducive atmosphere for learning and a focus on human relationships rather than technical and formal issues.