Introduction: Child sexual abuse (CSA) is a serious breach of a child's basic human rights. A variety of distressing short-term and long-term consequences might occur. Lack of reporting by the victims makes determination of actual prevalence rates for CSA difficult. Aim: This study aimed to assess the prevalence of child sexual assault and to identify factors related to its delay reporting by the victims.  Methods: This retrospective study was conducted in Benha Medico-legal Department, Ministry of Justice, from the start of 2016 to the end of 2018. Detailed medicolegal report of every case was obtained to fulfill personal data, assault data and data of general and local examination of the victims. Results: The total number of cases in the study was 155. Most of them were females aged between 12-18 years. Anal sex was more frequent among males (91.2%) while, rape, attempted rape, and mixed assault occurred only in females with statistically significant association between gender of victim and the type of sexual assault. It was found that gender of victim was significantly related to delayed disclosure. Additionally, there was a statistically significant association between both the victim's and the assailant's ages and delayed disclosure (p < 0.00). Conclusion: Sexual child abuse is a problem in our society and its reporting by the victims was often delayed. Recommendations: Female children should be encouraged by their families to report any attempt of sexual abuse early for proper documentation and protection of their rights. Furthermore, consistent methods and checklist for defining and reporting cases of CSA are required both in general hospitals and medicolegal institutions. There by proper preservation and collection of medical evidence could be achieved; to avoid the problem of lost data and the victim's rights.