Purpose: Farmers hold a key to reaching biodiversity targets, but will only carry out this service to society if they are sufficiently motivated to do so. The aim of this study is to evaluate the potential of on-farm advice as a tool for motivating farmers to take action to preserve or even to enhance biodiversity on their farms. Design/methodology/approach: To address this aim, we surveyed 133 farmers (response rate 43.9%), of whom 23 had received on-farm advice about farmland biodiversity conservation over a period of six years. Findings: The results showed that key beliefs and motivations were positively influenced by farmer advisory services. Farmers who had received advice agreed significantly more strongly in the compatibility of biodiversity conservation and production; that biodiversity is important; and that nature conservation on farms is appreciated by society. Practical Implications: These results allow the conclusion that on-farm biodiversity advice might be a useful way of positively influencing the beliefs and enhancing motivations of farmers to contribute to biodiversity conservation on their farms. Theoretical implications: Although several papers have examined the influence of agricultural extension on farmer behaviour, the results of this study contribute to explaining some of the contradictions in the literature about the effectiveness of advisory services. Furthermore, this study addresses [Batary, P., L. V. Dicks, D. Kleijn, and W. J. Sutherland. 2015. "The Role of Agri-Environment Schemes in Conservation and Environmental Management." "Conservation Biology" 29: 1006-1016.] challenge that there has been insufficient research on the link between farmer advice and the effectiveness of agri-environmental schemes. Originality/value: This paper is among the first to address these research gaps and is the first to examine the influence of advice on farmer conservation behaviour in the Swiss context.