Building ontologies is very important for diverse domains and especially for semantic Web. We find in the literature many methods and tools for this building. However, the fuzzy aspect is not enough studied in these methods and tools, whereas information systems can include uncertainties and imperfections. The goal of the definition of fuzzy ontologies is to integrate these characteristics. So, we must be able to modulate uncertainties, on the one hand, and to product representations accessible and understandable by machines, on the other hand. If we find actually many building methods and editors for classic ontologies (i.e., crisp or exact), we do not find such methods for fuzzy ontologies. Then, this paper defines our work for fuzzy ontologies building. It presents our fuzzy ontologies building method “Fuzzy OntoMethodology”.