The aim of this research is to investigate the incident of serial murders with a criminal psychology approach in Iran, which will address the dimensions of this issue by relying on library and documentary sources. Since scientific criminology cannot ignore social and individual issues arising from the functioning of the penal system, criminology has tended to focus on the way the penal system works, implementing the desired individualization of social reactions against crime, and for this purpose, we resort to clinical criminology to identify the factors affecting serial murders. Since serial killers often suffer from mental illnesses such as neurosis (neurosis) and mainly from the category of personality disorders (such as narcissism and antisocial personality disorder) and sexual disorders (such as other-harassment and cannibalism), they are among the mentally ill who cannot use insanity as a factor to remove criminal responsibility or exemption from punishment. In other words, they have full responsibility and are psychologically and legally responsible for their actions. Therefore; In the history of Iranian criminal law, no serial killer who has been tried has been able to escape responsibility or receive a lighter sentence based on their mental state; the same practice has been common in almost all other countries.