This study explores factors associated with farmers' decision to experiment with velvetbean (Mucuna spp.) , a green manure, as a maize intercrop in three villages of Veracruz, Mexico. T o assess whether velvetbean might be adopted on a wide scale in the region, the study also examines variation in farmers' perceptions of profits achieved by using the velvetbean intercrop compared to the farmers' usual practice. A stratified random sample of 92 households was selected from three villages reflecting differing conditions in the study area. All farmers who practiced in a velvetbean extension program in the previous year were included; a random sample was drawn of the remaining households in the villages. The analysis reveals that the current practice to which the farmers compared the maize/velvetbean intercrop played an important role in the perceived profitability of the new technology. Farmers who used neither herbicides nor fertilizer perceived a much larger positive difference in expected profits than farmers who compared the velvetbean intercrop with maize production using fertilizer or herbicides both. Farmers with opportunities to earn off-farm income were less likely to experiment with the velvetbean. Thus velvetbean may be adoptable on a wide scale by poorer farmers with limited access to chemical inputs and off-farm employment. However, these conclusions should be qualified in several ways. First, this study did not account for the full costs of using modern chemicals. Second. since the study was conducted, falling maize prices, coupled with higher prices for chemical inputs and more restricted availability of credit, may have made the intercrop more attractive to farmers. Third, the study was conducted early in the technology dissemination process, and farmers' judgements are based on only limited experience with velvetbean. Future experimentation with velvetbean, or another green manure in combination with inorganic fertilizer might prove acceptable to farmers and enhance the sustainability of maize production in ways that the use of chemical fertilizer alone could not do. It would also be useful if future research could assess whether velvetbean as an intercrop is actually more sustainable than current practices or whether social benefits of wide-scale velvetbean adoption would be greater than social costs.