Murder is one of the most serious crime which is resulting in the killing of another person. Therefore, it attracts the attention of the public and scientists who are trying to find the causes and to explain what leads to its commission. This paper provides an overview of different approaches that aim to explain the etiology of serial killers. The definition of a serial killer varies from author to author, and the most significant is the FBI's statement which says that a serial killer is a person who kills three or more people with a so-called cooling-off period between murders, which can last from several hours to several years. Serial murder is considered to be a compulsive act, committed either for arousal, sexual gratification, or domination. According to FBI estimates, there are more than 500 active serial killers in the world. Speaking of the etiology of serial homicides, it is important to mention that there are numerous criminological researches and theories that try to explain the causes of a serial homicide but many theories have a lack of scientific verification and mostly remain at the level of speculation.