||The impact of maize research and extension in Tanzania's Northern Zone during the past 20 years was evaluated through a formal survey in 1995. Data were grouped into two major agroecological zones: the intermediate and the lowland sub-zones. Sample farmers were also categorized based on land preparation method. A two-step Heckman's procedure was used to simultaneously analyze factors affecting adoption of improved maize seed and inorganic fertilizer. The study found that demand for composite seed was less than that for hybrids, although the National Maize Research Program had released more composites, which can be recycled. Farming experience was the only factor that significantly influenced the probability of adoption improved maize in the intermediate zone. No factor significantly influenced intensity of adoption of improved seed. About 80% of farmers recycled improved varieties, including hybrids, contrary to recommendations. The rate of adoption of chemical fertilizers was low, influenced only by the number of livestock units. No farm characteristic influenced intensity of fertilizer adoption. Recommendations on fertilizer placement were poorly followed, which magnifies the negative impact of the poor management of crop residues in the zone. Formal credit is not available to maize farmers; with rising input prices, this dynamic will become more critical. Adoption of recommendations on land preparation, frequency and timing of weeding and fertilizer application, and plant spacing have been successfully adopted in both zones. Recommendations based on survey results include the development of additional hybrids for the Northern Zone and/or village level production of composite seed; research on the economics of recycling improved varieties (including both composites and hybrids); more research and extension effort direct toward efficient use of fertilizers (manure, chemical fertilizer, and crop residues); and encouraging measures by banks and policy markers to make credit more available to small maize farmers with high rate of loan recovery and low cost of administration.