Purpose: In this paper, the knowledge dynamics of the farmer-rural extensionist' interface were explored from extensionists' perspective with the aim of understanding the matchmaking processes between supply and demand of extension services at the micro-level. Design/methodology/approach: Forty semi-structured interviews were conducted with extensionists whom work in the North-Eastern, Argentine provinces. Findings: Two different, general types of knowledge dynamics were identified: one moderately diffusionist, based on a hierarchical relationship and the prioritisation of experts' knowledge, and the other constructivist, based on horizontal processes of co-construction. Interestingly, some extensionists support beliefs pertaining to both approaches. They also highlight the importance of unceremonious trainings, interpersonal trust and making recommendations that take into account farmers' rationale. Practical implications: Results show the persistence of diffusionist rural extension and that extensionists have different, even contradictory, extension approaches, which renders inappropriate any attempt to generalise their perspectives. Theoretical implications: This study suggests that farmers' demand is the result of a constructive, interactive process, and thus is not prior to the interaction between the demand side (farmers) and the supply side (extensionists). Consequently, the knowledge and power dynamics that take place within the farmer-extensionist interface should be considered the nucleus of demand construction and the matchmaking process. Originality/value: This paper addresses the dynamic matchmaking process between supply and demand of extension services at the micro-level, suggesting it is a constructive process and showing the core role played by power dynamics.