This study documents how farmers modified an improved maize variety-with desirable characteristics for all farmers, but perceived as affordable only to the wealthy-into one appropriate for all, including the poor. Changes in the extent of adoption and associated farmers' perceptions of the improved variety V-524 in a community in Chiapas, Mexico over a nine-year period are examined. During the period this variety became ''creolized'' through farmers' management, which fostered hybridization between improved and local varieties. These results have implications for understanding how scientific technology is adapted to farmer conditions and for assessing the impacts of plant-breeding programs.