A DISSERTATION SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE IN AGRICULTURAL AND APPLIED ECONOMICS OF SOKOINE UNIVERSITY OF AGRICULTURE. MOROGORO, TANZANIAThis study analyzed the factors that influence the adoption of improved maize varieties and the extent of adoption in northern and eastern zones of Tanzania. Data were collected from a sample of 548 households in northern and eastern zones by adoption pathway project in 2013 by using household survey questionnaire. Descriptive statistics were employed to determine the improved maize varieties adopted in the two regions and Heckman two stage sample selection model was used to determine factors influencing the adoption and extent of adoption of improved maize varieties. Results from stage one of the Heckman model indicate that respondents who had 7 years and more in school and those who had communication and transportation assets were more likely to adopt improved maize varieties and was significant at (p ≤ 0.05), and respondent’s income and savings also significantly influence the adoption of improved maize varieties at p (≤ 0.1). The results of the second stage of the Heckman model indicate that respondent’s income and the difference in the two zones are significantly influencing the extent of adopting improved maize varieties. It is therefore concluded that farmers’ education, income, savings, zones and access to transportation and communication assets are the major factors influencing extent and adoption of improved maize varieties. And it is recommended that government and other development organization should create a favorable environment like subsidization of the farming technologies, improvement of rural infrastructures and strengthening farmers’ knowledge on modern agriculture production as the way of improving farmer’s adaptation to agricultural intensification practices.