A dynamic econometric framework (duration analysis) is used to analyze the determinants of farmers' decisions on whether or not to adopt low-external-input and sustainable agriculture (LEISA) technology. A wide range of potential determinants (both economic and non-economic) are considered. Our results suggest that the probability of a farmer adopting this technology increased if the farmer was more integrated with farmers' organizations, had contacts with nongovernmental organizations, was aware of the negative effect of chemicals on health and the environment, could rely on family labor, and had a farm located in an area with better soil conditions. On the other hand, the probability of adoption was reduced by increases in farm size. In addition, time-varying economic variables outside farmers' control were found to be significant determinants of adoption and the rate of diffusion. Changes in relative prices were particularly influential. Specifically, the diffusion of sustainable technology accelerated when declining output prices squeezed agricultural profit and many farmers faced difficulties in buying external inputs. Similarly, when labor became relatively cheap in periods of economic crisis, low-external-input practices became a more attractive option for family smallholdings. (C) 1998 Elsevier Science Inc.