Many authors suggest the need to define 'sustainable development' in operational terms. This paper looks at the problems of attempting to ask whether peasant farming systems are sustainable. Any attempt at sustainability assessment needs to consider issuesrelated to the selected indicators or performance criteria, spatialscale or boundaries, and temporal scale. While there is certainlya need for more rigorous analysis of sustainability issues, there is limited outlook for an approach based on indicators. Even if themany purely technical problems associated with specific indicators can be surmounted, will accurate bio-physical data advance our knowledge about sustainability? Peasant systems are politically-guided management systems, whose boundaries are the state,not the field or the farm. Key words: Peasant farming systems, Sustainability, Zimbabwe.