The research carried out in the project is presented in this book, which contains three main parts and nine chapters. This PhD thesis book is aimed at developing a competency profile for instructors in the agricultural extension services in Esfahan, Iran. Selected instructors are part-time subject matter specialists who cooperate with the Ministry of Agriculture and teach short-term extension courses in different disciplines to farmers. Previous research revealed that the target group of the research generally experience many problems in their role of instructor during extension courses for farmers. This PhD project was then conducted to develop a competency profile for this role in the next three to five years. In doing that, a comprehensive review of the literature was carried out, the competency models presented by McLagan (1982) were selected and adjusted to the Iranian extension system, and were tested for the role of instruction. To increase the reliability of the model, different respondents were involved: participating and non-participating farmers in extension courses, agricultural experts, agricultural managers, and instructors.