Recent studies have suggested that farmers' markets are increasingly important contributors to the economic development of rural and urban communities in the US. Yet, little is known about the specific ways and the extent to which farmers' markets contribute to developing their vendors' capacities as entrepreneurs or affect vendors' business success. In this study, we examine the capacities of farmers' market vendors in three states—New York, Iowa and California—and associated entrepreneurial outcomes. In particular, we explore how vendors' business activities and capacities are associated with different sizes of enterprises. A mail survey of up to 400 vendors, from 20 markets in each state, was conducted in 1999 to examine factors associated with business outcomes and vendor capacities. The importance of farmers' markets to small-, medium- and large-size enterprises and the particular contributions that have been most helpful to vendors were identified. Small-scale enterprises are still the most numerous at farmers' markets, making up almost 56% of all vendors. More than half of these enterprises are operated by part-time farmers or market gardeners. We found that the small enterprises had both less business and market experience, and sell at markets closer to home than do medium and large enterprises. Although these vendors with small enterprises have engaged in fewer entrepreneurial activities, made fewer business contacts and acquired fewer skills at farmers' markets, compared to medium and large enterprises they were more likely to consider farmers' markets to be their most important business development opportunity. Although, for these small enterprises, participating informers' markets may not yield financial gains as large as those gained by medium- and large-scale vendors, farmers' markets may be one of the few options for entrepreneurs to maintain and/or enhance their market niche in a community. Key information needs of small-, medium- and large-size enterprises are described, as well as suggestions for ways in which local educational institutions, Cooperative Extension, government agencies and nonprofit organizations can help support these enterprises and enhance community economic development in their regions.