(1) Background: The aim of the study was to analyse the structure of registered fatal violent crimes against children under 5 years of age and to identify the main characteristics and risk factors of fatal violence against children in order to discuss the possibilities and limits of prevention of these crimes. (2) Methods: Mixed-method design: 1. retrospective statistical analysis of data extracted from Czech statistics about crime. 2. qualitative analysis of autopsy reports and construction of serial case study. The data were pooled from two different sources: 1. Statistics about crime against children aged 0 to 5 (n = 512). 2. Autopsy reports (n = 52) of children up to the age of five. (3) Results: The following indicators and risk factors were identified: mental disorder or cognitive deficits in parents, parents’ immaturity, poor parenting skills, inadequate parenting practices, absence of a deep emotional bond with the mother, lack of parents’ interest in catering to the children’s needs, parents’ addiction, an unprotected, hazardous environment and surroundings, household falling apart, incidence of suspected domestic violence, incidence of multiple bruises and untreated injuries, aggressively dominant parents, poverty, absence of adequate health care, medical neglect of a child, poor health of the child and failure to thrive. (4) Conclusions: The task for the state is to make effective use of all accessible mechanisms to improve the situation in families. Particularly in the context of the newly emerging situation of increasing uncontrolled violence in families in the context of the restrictions of the COVID-19 pandemic, this demand is more than urgent. Close attention should be paid to children who are not registered with pediatricians and fail to attend regular medical examinations. It is also vital to follow families in which violence has already been suspected in the past.