Paper gives an outline of the ethical principles of research in biomedicine and psychology. Ethical principles to be observed in conduct of biomedical research involving human subjects are conditio sine qua non for a licit performance of clinical research studies in humans. They are concerned primarily with the protection of human dignity, rights, integrity and well-being of the human research subjects. Their observance, together with a proper methodological design of the research and practical implementation of the standards of Good Clinical, Laboratory and Scientific Practices ensure also the credibility of research data obtained.