Farmer-to-farmer transfer or dissemination of technologies is a neglected area of research even though successful diffusion of many researcher and farmer-developed technologies is highly dependent upon farmers' private initiatives. This is particularly true in many developing countries where formal market mechanisms used in dissemination are often ineffective. Successful dissemination of new technologies to marginal farmers require greater knowledge and use of indigenous dissemination methods. The determinants of farmer-to-farmer transfer of new bean varieties experimented with by small-scale farmers in Uganda are investigated. Farmers were experimenting with new varieties received through earlier on-farm trials and were transferring small quantities of grain to other farmers for experimental purposes. On-farm trials may thus be an effective, but limited method for diffusing new varieties. Factors directly associated with the transfer decision were farm size and variables identifying a willingness to experiment with new varieties. The Production risk reducing strategies of intercropping and sowing of a larger number of non-climbing bean varieties were negatively associated with the probability to transfer grain. The quantity of grain available to transfer was not associated with the transfer decision. Farmers were not transferring grain of the five varieties at different rates even though significant differences in yield were found.