We discuss fuzzy implications of fuzzy cognitive map (FCM), which has been used in various fields for representing causal knowledge. To accomplish this objective, fuzzy implications of FCM are thoroughly investigated with extensive examples. FCM is a fuzzy signed digraph with feedback, which can model the real world as a collection of concept variables and causal relationships. Therefore, FCM has been used as a new knowledge acquisition scheme in expert systems domain, especially in abstract and fuzzy domains where the relationships between concept variables are causal. However, fuzzy implications of FCM have been misunderstood, leading to the misuse of FCM. In this sense, we reveal new fuzzy implications of FCM and use them for forming causal knowledge. Those fuzzy implications proposed herein include fuzzy causal relationship and fuzzy partially causal relationship. Extensive definitions and theorems are proposed to show the validity of our proposed fuzzy implications.