This final paper deals with the topic of ethics and morals in sport, namely their greatest "enemy" – drugs. To begin with, we will get acquainted with the concepts of ethics and bioethics of sport and see what the situation is in Croatian sport, at least as regards ethics. Furthermore, we will talk about morality and how he is connected with sports. In today's sport a great moral problem is drugs and taking illicit substances to achieve better results. The main problems of this work are precisely that – drugs and how their consumption can affect the individual. We will talk about influence of drugs on psychological and physical levels as well as the consequence of taking drugs in sports (both physical and professional). Each procedure carries its own consequences and thus the use of illicit substances in the world of sport. The consequences for athletes found to have used drugs or any illicit substances can be large, not only in sports, but also in legal side. At the end of the paper I will look back on how the criminal responsibility for the use of the aforementioned substances is regulated in Croatia. As a thesis, the question arises: can you say that doping seriously shook the ethical and moral foundations of sport? Keywords: ethics, morality, drugs, Zakon o sportu ( Act of sports )