Experience in nutrition interventions points to several design characteristics of field programmes which could improve their effectiveness. Regular government extension services have the potential to reach large numbers of people, yet staff will require additional training to respond to the changing demands of field work. A new approach to training such staff has been developed by the Food and Agriculture Organization. The approach provides staff with information and managerial skills that are common to all extension work. The practical examples used to introduce these techniques illustrate nutritional problems that fieldworkers face and give a measure of confidence in finding solutions. Training materials based on this approach are presently used by several governments.