Huge image collections have been created, managed and stored into image databases. Given the large size of these collections it is essential to pro- vide efficient and effective mechanisms to retrieve images. This is the objective of the so-called content-based image retrieval - CBIR - systems. Traditionally, these systems are based on objective criteria to represent and compare ima- ges. However, users of CBIR systems tend to use subjective elements to compare images. The use of these elements have improved the effectiveness of content- based image retrieval systems. This paper discusses approaches that incorpo- rate semantic information into content-based image retrieval process, highligh- ting some new challenges on this area.