The paper presents the most important criminological theories and results of contemporary criminological research with the aim of identifying the etiologic factors (risky and protective) that affect the occurrence of criminal behavior. Certain psychological, biological and social variables have been identified that, to a greater or lesser extent, depending on the social context and the various developmental periods, affect the individual who can become a perpetrator but also a victim of a criminal offense. Thus, correlations have been established in the area of personal characteristics such as gender, age, education, intelligence, aggressivity, religiosity and so on and in environmental factors such as the closer and broader social environment (family, peers, neighborhood and local community). Each of these factors can have a risky or protective role in the development of delinquent behavior and victimization. Contemporary authors agree that individual risk or protective factor is not self-sufficient enough for the development of criminal behavior and that the likelihood of criminal behavior and criminal recidivism increases not only with an increased number but also with the intensity of influence of certain risk factors. In that sense, this paper has outlined some features that shape both offenders and victims of criminal acts because of the specific constellation of endogenous and exogenous risk factors and can therefore serve as a starting point for planning specific preventive programs.