Colonoscopy is a routine procedure performed worldwide, nevertheless, a small risk of splenic injury, often underestimated , is still present. As a matter of fact, the diagnosis may be delayed, leading to a rising risk of morbidity and mortality. This paper describes a case of conservative treatment of colonoscopy-associated splenic injury. A 57-year-old woman presented with worsening pain in the upper left abdominal quadrant; she had radiation therapy to the ipsilateral subscapular region, and a diagnostic colonoscopy 18 hours earlier. The computed tomography (CT) scan revealed splenic laceration without signs of hemoperitoneum. Because of the hemodynamic stability of the patient, successful conservative treatment and serial controls of the blood and hemodynamic parameters were adopted. Even if rare splenic injury during colonoscopy is associated with significant morbidity and mortality. A high degree of clinical suspicion is essential to achieve a prompt diagnosis as well as an early surgical evaluation. The nonoperative approach is usually taken in patients with no intraperitoneal bleeding, a closed subcapsular haematoma and a stable hemodynamic status.