ABSTRACT This paper examines the adoption and assessment of improved maize varieties by farmers in Institute-of-Agricultural-Re-search-&-Training-adopted villages in Southwest Nigeria. Specifically, the study determined the level of awareness and adoption of the maize varieties disseminated to farmers; compared the performance of the farmers' variety with the improved varieties; ascertained the effect of the technologies on farmers; and analysed the personal, socio-economic and varietal factors influencing the adoption of maize varieties in the study area. Data were collected from sixty-four (64) maize farmers selected from the two adopted and surrounding villages representing the two broad agroecologies (forest and derived savanna) of Southwest Nigeria. The result indicates that the awareness of the improved maize varieties was high (71.5%) and, consequently, the adoption was also high (56.7%). The ranking of the maize varieties showed that a majority of the farmers preferred the DMR-ESR-Y (a yellow-grained and early-maturing variety) to the other varieties. Also, empirical evidence reveals that age, household size, education, and varietal attributes were the most important factors that influenced the adoption of improved maize seeds. Generally, farmers preferred these varieties, which mature early, had low production risks, and good market value. The farmers identified the benefits of improved maize varieties as improved yield (68.7%), household food security (68.7%), reduction in labour use (67.1%), and increased income (53.1%). Future research should consider farmers' characteristics as well as their participation in the research process of technology generation and dissemination—especially on-farm field trials for varietal selection—so as to reduce some of the problems inherent in the improved varieties as described by farmers.