Abstract
People depend on animals for different goals; and one of these goals is research. But, using animals in research is a very controversial issue. The purpose of this paper is discussing the controversial issue of usinganimals in research from different point views and clarifies the evidences that each opinion based on. The review is comprehensive rather than systematic, and is limited to literature available in online databases. It was concluded that the trends supporting using animals in research are more acceptable and convincing.