The Authors mention the historical evolution that led to consider the splenectomy as the ideal operation in patients with post-traumatic lesions of the spleen. They linger then on the actual knowledges about the physiopathology of this organ that determined a substantial change of mind to a conservative treatment, when possible. By reporting their experience of the last decade, they weigh up how every therapeutic choice must be consequent to an accurate clinical evaluation that suggests the surgical abdomen exploration in urgency or, on the contrary, the monitoring of the patient. They linger particularly on the validity of the investigation and quantization of organ lesions and of the subsequent hemoperitoneum. The Authors end affirming that an accurate diagnostic evaluation and the subsequent therapy must take place in a specialized Trauma Center that ensures intensive monitoring and, if necessary, a timely operation in these patients.