The aim was to determine blood loss degree in case of spleen trauma in children and to justify safety of victims treatment without surgery. Materials and methods. It was performed retrospective cohort study of 105 autopsies of children who died of combined trauma. 33 of them had spleen injury. Prospective cohort study was performed in 75 children with spleen injury, 69 (92%) from whom were treated without surgery. Results. It was established that thanatogenetic feature of spleen injury in children is moderate blood loss (89.6% of victims), incidence of large and massive blood loss was 6.8% and 3.4% respectively. In unoperated children blood loss did not exceed 15% of blood volume. In group of operated children (n=6; 8%) incidence of large blood loss was 4% (n=3) and did not exceed 28% of blood volume. Prevalence of moderate blood loss in case of spleen trauma due to anatomic and physiological features and mechanisms of spleen injury is theoretically justified.