Farmers have to decide on various issues while carrying out their agricultural activities. There is a significant impact on the knowledge that the farmers have in making the decision. While scientific knowledge is the produced by research institutions and transmitted to farmers through extension organizations, local knowledge is reflect cultural and society features and it transferred next generations. So previous generations are local sources of information.Local knowledge is helping to make decisions about agriculture, health, education, natural resource management. Local knowledge is data for agricultural extension studies. Thanks to this knowledge extension institutions are learning about the farmers' current conditions and practices and building their extension programs on this knowledge. On the other hand, local knowledge protects biodiversity and preserves local genetic resources, while agricultural heritage protects natural resources through low-input agricultural production. It is also important to ensure food safety, as local knowledge is an alternative production technique when modern farming technologies do not comply locally with farmers' requirements. When an assessment is made in terms of agricultural extension, local knowledge appears to be an important source of knowledge. Because farmers provide important information from family members, friends and neighbors. The farmers' own experiences are also an important source of information. In this study will be examine the differences between local knowledge and scientific knowledge, the characteristics of local knowledge, local knowledge types, extension approaches that respect local knowledge, and the importance of local knowledge in terms of agricultural extension.