Agricultural production is influenced by different political, economic and environmental factors. Various factors influence production, affecting the income of farmers and even in some cases increasing their vulnerability. Continuation and expansion of economic activity in this sector requires appropriate risk management policies to be promptly and appropriately applied. One of the oldest strategies for risk management in the agricultural sector is the diversity of crops grown. In this study, factors affecting the decision in cultivating various crops by farmers in Mazandaran province (for years 2008 to 2009) with an emphasis on extension activities, has been studied. The variables: farmer's experience, number of farm labor, farm size, number of educational courses, participation in and understanding of the extension programs, were some of the factors affecting the use of diversified crop culture by farmers. The highest estimated coefficient among different variables was related to the variable of participation. Hence the adoption of appropriate plans along with the use of services of experts in expanding the diversity of crops in this region can be constructively effective.