Scientists planning research that involves the use of animals are required by international and/or national law to examine the possibilities for the implementation of Replacement, Reduction and/or Refinement (the Three Rs principles of Russell and Burch) in experiments for research, testing, and education. There are two Korean laws legislating humane use of animals and ethical review prior to animal experiments. This report reviews current practice of the literature search by the researchers and protocol review by the Institutional Animal Care and Use Committees on the Replacement, Reduction and Refinement alternatives in Korea. The promotion and protection of the laboratory animals are one of the core competencies of investigators exploring the ethical conduct of research and good science.