This report is based on a study of the adoption and use of improved open-pollinated varieties and hybrids by small-scale farmers in the Department of Jutiapa, Guatemala. The majority of maize producers in Guatemala are small-scale subsistence farmers. Approximately 60% of the basic grains produced in the country are grown on farms that are too small to satisfy the basic nutritional needs of a typical family (5-6 persons). Increasing yields through the use of new technologies is seen as a critical step to ensuring adequate nutrition and increasing farmer income in the area. The study, conducted in June and July 1991, randomly surveyed 208 farmers in 18 municipalities of Jutiapa, apportioned according to the number of farms in each municipality. There was particular interest in assessing the impact of the Project of Generation and Transfer of Agricultural Technology and Seed Production (PROGETTAPS), which was launched in 1986 by the Instituto de Ciencia y Tecnología Agrícolas (ICTA) and the General Directorate of Agricultural Services (DIGESA) with the goal of increasing small-scale farmers access to improved seeds. Study findings reveal a complex pattern of seed use in Jutiapa. Although the farmers there use several types of local and improved maize seed, they seem to prefer and use the local variety known as Arriquin, as well as two improved materials: an open-pollinated variety (B-1) and a hybrid (H-5). The reported forms of acquisition and preferences indicate that most of the farmers use the same material from 1 to 3 sowing seasons. Yield gains and relative prices, two important factors determining the profitability of adoption of new varieties, are adequate. By changing from their local varieties to OPVs and hybrids, farmers most likely can expect yield increases ranging from 35% to 70%. The decision to use improved materials in part or all of the area cropped with maize is associated with a change in the maize cropping system. Results suggest that farmers that sow a plot of maize in monoculture tend to plant the entire area with improved seed, particularly with hybrids. Results also show that the size of the family, taken together with the cropping system, is an important factor influencing the probability of full adoption, particularly of hybrid materials. The findings indicate that the probability of using hybrid materials, either in part or all of a cropped area, increases with farm size. Importantly, results from the estimating model confirmed the trend observed at the aggregate level. PROGETTAPS had a significant impact on the adoption of OPVs in Jutiapa. Farmers that have experience with PROGETTAPS are more likely to adopt OPVs than those who do not have contact with it. Furthermore, the probability of adoption increases with the years of association farmers have had with the program.