The transaction of agricultural products, which take place in the local farmers¡¦ market, has a variety of modes. According to Oliver. E Williamson (1991), the characteristics of transactions differ from incentives intensity, administrative control, and performance attributes. Based upon the foregoing, agricultural transaction modes in the local farmers¡¦ market distinctions into three kinds: (1) market mode (2) hybrid mode, and (3) hierarchy mode. The purpose of this study is attempting to abstract the crucial dimension of agricultural transactions for organizing some transactions this way and other transactions another. The overall objectives of this study can be said to be threefold: (1) To investigate and collect literatures about the agricultural transaction modes which are presently most popular in Taiwan. (2) To identify and distinguish these transactions into market mode, hybrid mode, and hierarchy mode as suggested by Williamson. (3) As an exploratory study, to suggest uncertainty as the crucial dimension of agricultural transactions alternatives, to demonstrate why and how uncertainty rule on the selection decision. The results from this study suggest that: (1) When the uncertainty of agricultural transactions is high, hierarchy mode appears to be feasible relatively. (2) When the uncertainty is low, market mode appears to be feasible relatively. (3) When the uncertainty is in an intermediate situation, hybrid mode appears to be feasible relatively. A case study of the broiler contracts of the Charoen Pokphand Enterprise (Taiwan) Co. shows that the relationship between feasible contract mode and uncertainty of transaction is consistent with theoretical expectation.