Australia is one of the most urbanised countries in the world, with some 90% of the population living in cities. Only 6.1% of Australia's land mass is considered of arable quality, compared to 17% in the USA. Moreover, the amount of peri-urban land available for food cultivation is diminishing as urban sprawl expands to accommodate a growing population. The advent of 'industrial' agriculture in the 19th and 20th centuries marginalised urban agriculture but the past 20 years have seen a resurgence in public and policy interest and activity in numerous cities and countries. The research and data which should underpin such renewed and increased interest and activity, however, remain ad hoc and largely anecdotal. A more informed approach is now both urgent and essential. The growth of cities generates benefits - notably by creating centres of economic development and innovation - but also detriments, by way of sedentary lifestyles and obesity, stress and mental ill-health, crime and loss of community cohesion. There is international evidence that urban agriculture may help reverse these trends through its positive effects on diet, health and wellbeing and the social fabric. In addition, urban agriculture responds to the challenges of climate change, both through mitigation (reducing 'food miles' and carbon footprint) and adaptation (substituting for those rural areas where agriculture may no longer be viable). This paper reports on the first stage of a broader project which aims to develop an evidence base for policy, planning and design to facilitate urban agriculture in Australian cities. This stage relates to the identification of available space to support quantification of food production potential. While Sydney is the focus, care is taken to ensure that the final methodology used will be transferable. One way to increase the quantity of agricultural land in built-up areas is to cultivate informal green spaces such as vacant lots, street and railway verges, and also the rooftops of existing buildings. Determining the potential for urban food production requires application of a range of methods to ascertain the location, spatial extent, distribution and ease of access to suitable spaces, including such 'leftover' spaces. These methods include remote sensing (LiDAR, satellite and aerial imagery) and field verification, and also space syntax. The main focus of this paper is to explore space syntax techniques in relation to their capacity to quantify the accessibility of potential sites, their interrelationships as elements of an urban agriculture network and their integration with the broader city fabric. The longer term objective is to derive a database of potential urban agriculture sites in inner and outer metropolitan regions, categorised in terms of the ease with which local residents can get to individual sites by walking or cycling, the proportion of city dwellers able to easily reach an urban farm, the potential number of users at the local scale, the inter-accessibility of sites at the city-wide scale and the spatial diversity of prospective sites.