Abstract
The concept of Semantic Web has introduced an important form of knowledge representation - ontology. As a hierarchical structure of concepts together with their definitions ontology provides means for expressing semantics of data. The ability to build rules with ontology concepts and to perform reasoning increases its attractiveness even further. This paper proposes a framework for expressing fuzzy temporal information using ontology. The framework is built based on ontology suitable for expressing facts and building rules that include fuzzy and temporal terms. This proposed fuzzy temporal ontology can be imported to any domain ontology and used a knowledge base in variety of applications. The paper includes description of build-in predicates needed for constructing fuzzy temporal rules. Simple examples of application of the predicates are presented.