Internet is an important component in technology development, including, toursm. Tourism is an industry which involves much information needed for traveling.Many tourists search for travel information in the web. Nevertheless, the web often gives irrelevant information. Besides that, a huge size of information in the web and the spread of the information in many different sources make users need more time in searching for information and organizing them from many different sources manually. Semantic web is a solution to solve those problem by providing knowledge based on an ontology. E-tourism is a good domain for implementing the semantic web because there are many information sources and data exchange involved in the e-tourism. In this paper, a knowledge base which is based on an ontology is designed and built using protege tool version 3.4.7. The ontology consist of tourism domain specific information and stores data of accommodation. attraction, and cultural event in Bali which is one of the main travel destination in indonesia. Besides that, a search engine application for e-tourism in bali, which implements the semantic web, is designed and built using RAP-RDF version 0.9.6 and RDF query language SPARQL so that the search results conform to the ontology.